Deck 8: Parameter Estimates

Question 1

Whenever a sample is selected and measured, one must assume that the sample mean

A) will probably differ from the population mean
B) will probably be identical with the population mean
C) will over-estimate the population mean
D) will under-estimate the population mean

Answer 1

A

Question 2

When an area (between high and low values) of the sampling distribution of means have been bracketed on the basis of a reasonable expectation of containing (estimating) the population mean, then

A) the central limit theorem has been proven
B) the point estimate has been proven
C) the alpha level has been calculated
D) the confidence interval has been calculated

Answer 2

D

Question 3

Increasing the confidence-interval level from .95 to .

A) increases the likelihood of including the population mean within its limits
B) decreases the likelihood of including the population mean within its limits
C) increases the number of degrees of freedom
D) none of these, since a confidence interval may never include the true population mean

Answer 3

A

Question 4

According to the text, the highest value that should be assigned to the alpha level is

A) .95
B) .99
C) .10
D) .05

Question 5

Other things being equal, an alpha level of .05 should lead to a rejection of the null hypothesis

A) more often than when alpha is set at .01
B) more often than when alpha is set at .10
C) less often than when alpha is set at .01
D) none of these, since when alpha is set at .05, the null hypothesis cannot be rejected

Question 6

The single-sample t ratio is used to compare

A) two population means
B) a sample mean with an assumed or known population mean
C) two sample means
D) a single sample's mean with that same sample's standard deviation

Question 7

Other things being equal, the higher the value of the t ratio

A) the greater the likelihood of rejecting Ho
B) the less the likelihood of rejecting Ho
C) the more certain that the samples represent a single population
D) the greater the likelihood of sampling error

Question 8

Rejecting Ho when in fact we should have failed to reject it, causes the

A) standard error
B) sampling error
C) omega error
D) Type 1 error

Question 9

When we fail to reject null hypothesis, then we know for certain that

A) the mean of the sample equals the mean of the population
B) the mean of the sample differs from the mean of the population
C) the mean of the sample is a biased estimator
D) none of these, since the statistical decision is a probability statement and not a

Question 10

The fact that the point estimate of the population mean may be inaccurate (even with random sampling) is due largely to

A) bias
B) alpha error
C) sampling error
D) none of these, since the population mean cannot be estimated

Question 11

A single-sample t ratio is only considered to be significant when

A) the population values are known
B) the population values are assumed
C) its value falls within the confidence interval
D) the null hypothesis has been rejected

Question 12

For the t ratio, the larger the sample size

A) the larger the alpha level
B) the larger the beta level
C) the larger the number of groups being compared
D) the larger the number of degrees of freedom

Question 13

When the null hypothesis is rejected, then we know for certain that

A) the mean of the sample equals the mean of the population
B) the mean of the sample differs from the mean of the population
C) the mean of the sample is a biased estimator
D) none of these, since the statistical decision is a probability statement and not a statement of certainty

Question 14

Estimating the value of the population mean on the basis of the sample mean alone produces a(n)

A) parameter
B) point estimate of a parameter
C) estimated statistic
D) none of these, since the population mean cannot be estimated

Question 15

With a single-sample t ratio, the null hypothesis states that

A) the sample mean could readily be part of the same distribution whose overall mean is already known.
B) the sample mean in all likelihood could not be part of the same distribution whose overall mean is already known
C) the sample mean and the population mean are significantly different values
D) none of these, since the null hypothesis always assumes that at least two sample means

Question 16

When a given difference is determined to be "significant", then

A) the alpha level must have failed
B) the alpha level must have been rejected
C) the null hypothesis must have been rejected
D) there was a failure to reject the null hypothesis

Question 17

A single-sample t ratio presents the difference between two means in units of

A) the estimated standard error of the mean
B) the estimated population standard deviation of the underlying distribution of individual scores
C) the estimated standard error of difference
D) none of these, since the single-sample t ratio cannot compare two means

Question 18

If it is determined that there is no difference between the population mean being represented by the sample and the mean of the population at large, then

A) the alpha level must have failed
B) the alpha level must have been rejected
C) the alpha level must have been committed
D) there was a failure to reject the null hypothesis

Question 19

The true population mean is expected to fall outside a .99 confidence interval

A) 1% of the time
B) 99% of the time
C) 100% of the time
D) none of these, since the true mean may never fall outside the confidence interval

Question 20

A point estimate of a population value is referred to as

A) a biased estimator
B) a true parameter
C) a true variability measure
D) an hypothesized parameter

Question 21

The Type 1 error states the probability of being wrong whenever

A) There is a failure to reject Ho
B) Ho is rejected
C) Ho is tested
D) the sample means are assumed to be equal

Question 22

The relationship between the exact value of alpha and the number of degrees of freedom, is that

A) the greater the alpha level, the greater the degrees of freedom
B) the smaller the alpha level, the greater the degrees of freedom
C) degrees of freedom and alpha level take on the same value
D) none of these, since the alpha level and degrees of freedom are unrelated

Question 23

The estimated standard error of the mean can be calculated on the basis of the information

A) provided by a single, individual score
B) provided in a single sample
C) provided by comparing two sample means
D) provided by comparing a pair of parameters

Question 24

The estimated standard error of the mean takes on a negative value only when

A) most of the samples are below the mean
B) populations of less than an N of 30 are involved
C) populations of more than an N of 30 are involved
D) none of these

Question 25

When estimating the population mean on the basis of the information contained in a single sample, one must at least know

A) the estimated standard error of the mean and the mean of the sample
B) the z score for each raw score
C) the standard deviation of the underlying distribution of individual scores
D) the interdecile range

Question 26

The estimated standard error of the mean is equal to

A) the standard deviation of the sample
B) the standard deviation of the sample, divided by the square-root of the size of the sample, less one
C) the standard deviation of the population multiplied by the size of the population
D) the difference between the mean of the sample and the mean of the

Question 27

In order to reach a confidence level of .95, then alpha must be set at

A) .05
B) .95
C) .99
D) none of these

Question 28

Whenever Ho is rejected, then

A) it is possible to commit the Type 1 error
B) it is impossible to commit the Type 1 error
C) the only possible error is sampling error
D) none of these

Question 29

If a researcher were to conduct 100 experiments, and in each case the null hypothesis were rejected at an alpha of .05, then

A) chances are that 5% of the decisions were incorrect
B) chances are that 95% of the decisions were incorrect
C) chances are that less than 5% of the decisions were correct
D) none of these, since null can never be rejected 100 times in a row

Question 30

Whenever the calculated value of t is equal to or greater than the tabled value of t, for a given number of degrees of freedom, then

A) There is a failure to reject Ho
B) Ho is rejected
C) Ho is no longer relevant
D) the alpha level becomes zero

Question 31

For the t test, other things being equal, the smaller the value of the alpha error

A) the less likely it becomes to reject Ho
B) the more likely it becomes to reject Ho
C) the fewer the degrees of freedom
103
C) the less likely it becomes to fail to reject Ho

Question 32

The relationship between the alpha level and the confidence level is such that

A) the lower the alpha, the higher the confidence level
B) the lower the alpha, the lower the confidence level
C) they are not related until the confidence level reaches .95
D) none of these, since they are not related at all

Question 33

The estimated standard error of the mean is

A) an estimate of the sampling error
B) a parameter
C) a statistic
D) equal to the range of individual scores, divided by 6

Question 34

When alpha is set at .05 and Ho is rejected, then the probability is

A) .95 that there was a failure to reject Ho
B) .95 that Ho should not have been rejected
C) .05 that Ho should have been rejected
C) .95 that Ho should have been rejected

Question 35

For the t ratio, the larger the difference between the sample mean and the population mean (other things being equal), the greater the likelihood of

A) rejecting Ho
B) failing to reject Ho
C) sampling error
D) committing the standard error

Question 36

Multiplying the estimated standard error of the mean by 6 yields an approximation of

A) the range of the entire distribution of individual scores
B) the range of the entire sampling distribution of means
C) the standard deviation of the sample
D) the standard deviation of the population

Question 37

In order to calculate the estimated standard error of the mean, one need only know

A) the sample's standard deviation and the size of the sample
B) the sample mean
C) the parameter mean
D) the standard deviation of the distribution of individual scores

Question 38

Whenever the calculated value of t is less than the tabled value of t (for a given number of degrees of freedom), then

A) There is a failure to reject Ho
B) Ho is rejected
C) Ho is no longer relevant
D) the alpha level increases

Question 39

The estimated standard error of the mean becomes a better predictor whenever the distribution of sample means

A) is skewed
B) is bimodal
C) is platykurtic
D) none of these

Question 40

The estimated standard error of the mean is always used to predict

A) sample size
B) bias
C) central tendency
D) the variability of the distribution of sample means

Question 41

The term "confidence" expresses the probability that one's estimate is

A) accurate
B) not accurate
C) inferred from a population
D) based on a sample mean

Question 42

When the confidence interval has a probability value of .99, then

A) the resulting prediction is never wrong
B) the resulting prediction is wrong 99% of the time
C) 99% of the resulting predictions are assumed to lie within the interval
D) none of these, since the confidence interval has nothing to do with

Question 43

In order to predict whether a certain set of random sample scores could possibly be part of a given population, the researcher could use

A) the z score equivalents of each sample score
B) the percentile equivalents of each sample score
C) the one-sample t test
D) the interdecile range

Question 44

A point estimate predicts a single parameter-mean value.

Question 45

The techniques of inferential statistics are based on a probability model, and may sometimes lead to inaccurate predictions

Question 46

The estimated standard error of the mean can only be calculated when the entire population of individual scores are available.

Question 47

For the t ratio, other things being equal, having 1 degree of freedom rather than 12 degrees of freedom makes it

A) more likely to reject Ho
B) less likely to reject Ho
C) impossible to reject Ho
D) none of these

Question 48

The higher the probability value of the confidence interval

A) the broader becomes the range of predicted mean values
B) the more narrow becomes the range of predicted mean values
C) the less the sampling error
D) the greater the sampling error

Question 49

The estimated standard error of the mean is to the standard deviation of the entire distribution of all possible sample means as

A) a statistic is to a parameter
B) a parameter is to a statistic
C) a parameter is to an estimate
D) a deviation score is to a raw score

Question 50

The alpha level specifies the probability of being correct when rejecting null.

Question 51

When the parameter mean is predicted to lie within a certain range of mean values, the technique employed is called

A) point estimation
B) error estimation
C) interval estimation
D) inferential validity

Question 52

With very small sample sizes, the estimated standard deviation of the population yields a slightly higher value than does the true standard deviation of the sample.

Question 53

The estimated standard error of the mean may be calculated on the basis of the information contained in a single random sample.

Question 54

The standard error of the mean may never be negative.

Question 55

The Type 1 error may never be committed when

A) Ho is rejected
B) There is a failure to reject Ho
C) the direction of Ha is specified
D) none of these, since there is always some possibility of committing the Type 1 error

Question 56

The true parameter mean may be predicted by using

A) either hypothesis testing or known variance values
B) either hypothesis testing or interval estimation
C) either interval estimation or its opposite, confidence intervals
D) none of these

Question 57

The true mean of the population must always be a known value before inferential techniques may be employed.

Question 58

A confidence interval of .99 predicts a narrower range of mean values than does an interval of .

Question 59

Other things being equal, the fewer the degrees of freedom, the easier it is to obtain a significant t ratio.

Question 60

When the parameter mean is predicted as a single value, the technique employed is called

A) point estimation
B) error estimation
C) interval estimation
D) inferential validity

Question 61

When there is a failure to reject Ho, one must conclude that the difference between the sample mean and the population mean is probably not due to chance.

Question 62

The concept of the standard error of the mean indicates that the actual population mean can never be a true parameter.

Question 63

The actual mean of the set of sample scores may be used directly to estimate the point value of the population mean.

Question 64

When subjects are selected randomly, then the larger the sample size, the higher the likelihood of the sample mean approaching the population mean.

Question 65

Parameter estimates are considered to be hypotheses.

Question 66

The Type 1 error is committed when here is a failure to reject Ho when in fact it should have been rejected.

Question 67

Other things being equal, the smaller the value of the estimated standard error of the mean, the narrower the confidence interval becomes.

Question 68

Other things being equal, increasing the sample size, decreases the width of the confidence interval.

Question 69

Negative t ratios may sometimes lead to significant results.

Question 70

The true standard deviation of the sample may be used directly to estimate the point value of the population mean.

Question 71

The concept of the standard error of the mean implies that the estimated population standard deviation must yield a value which over-estimates the true mean.

Question 72

The only t ratios which can possibly lead to a reject of the null hypothesis are those which are positive in sign.

Question 73

The alpha level is typically set at either .95 or .99.

Question 74

A significant difference is one that is probably not due to chance.

Question 75

Because of sampling error, the point estimate of the population mean may produce an inaccurate prediction.

Question 76

The true standard deviation of the entire distribution of random sample means is defined as the standard error of the mean.

Question 77

With a sample size of 30, the single-sample t ratio has 1 degree of freedom.

Question 78

Regardless of sample size, the degrees of freedom assigned to the single-sample t ratio must remain constant.

Question 79

Other things being equal, a .99 confidence interval produces a wider interval than when the confidence level is set at .

Question 80

Interval estimates, unlike point estimates, are used to predict a single parameter value.