Question 1

For inference about single means, df is

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)    D

Question 2

The Director of Student Health Services wishes to know if her anti-smoking campaign has been effective. Last year, a complete survey of all students found the mean number of cigarettes smoked per day by students to be 8.6 with a standard deviation of 2.0. The Director of the Student Health Service obtains the following results from a recently selected random sample of students (in cigarettes smoked per day): 
   
(a)Set up 
   
 and 
   
(b)Perform the statistical test (
   
(c)Draw final conclusions.

Accepted Answer

(a)    
< 8.6
(b) 
   
reject
   
(c) Conclude that the campaign was effective in reducing smoking among students.

Question 3

If   
 and 
   
 and the critical values of z are 
   
 when 
   
 and 
   
 when 
   
 what would we do if our calculated value of z were -2.80?

Accepted Answer

A)  retain 
   at 
 
   but reject it at 
   
B)  retain   
 at   
 
 and retain it at 
   
C)  reject   
 at 
   
 but retain it at 
   
D)  reject   
 at 
   
 and reject it at 
   
A)  retain 
   at 
 
   but reject it at 
   
B)  retain   
 at   
 
 and retain it at 
   
C)  reject   
 at 
   
 but retain it at 
   
D)  reject   
 at 
   
 and reject it at 
   D

Question 4

We conduct a two-tailed test at the .05 significance level with data that afford 8 degrees of freedom. When we look up the critical value of t, we will expect it to be ____________ the corresponding critical value of z.

Accepted Answer

A)  substantially larger than 
B)  the same as 
C)  slightly smaller than 
D)  either larger than or smaller than, depending on n 
A)  substantially larger than 
B)  the same as 
C)  slightly smaller than 
D)  either larger than or smaller than, depending on n

Question 5

When the value of   
 is changed from .05 to .01,

Accepted Answer

A)  the standard error of the mean is reduced 
B)  the significance level is lowered 
C)  the more deviant a sample mean must be before it leads to rejection of the null hypothesis 
D)  both (b) and (c) are true 
A)  the standard error of the mean is reduced 
B)  the significance level is lowered 
C)  the more deviant a sample mean must be before it leads to rejection of the null hypothesis 
D)  both (b) and (c) are true

Question 6

We are thinking of a two-tailed test, but decide on a one-tailed test. This means that

Accepted Answer

A)  the critical value of t will be numerically less 
B)  the critical value of t will be numerically greater 
C)  the value of $\alpha$ should be changed 
D)  the null hypothesis will be stated differently 
A)  the critical value of t will be numerically less 
B)  the critical value of t will be numerically greater 
C)  the value of $\alpha$ should be changed 
D)  the null hypothesis will be stated differently

Question 7

As the number of degrees of freedom increases, student's distribution of t

Accepted Answer

A)  remains the same 
B)  changes slowly at first, then more rapidly 
C)  changes rapidly at first, then more slowly 
D)  changes at an even rate 
A)  remains the same 
B)  changes slowly at first, then more rapidly 
C)  changes rapidly at first, then more slowly 
D)  changes at an even rate

Question 8

In general, "degrees of freedom" is most closely related to the

Accepted Answer

A)  level of significance 
B)  value of   
C)  value of   
D)  sample size 
A)  level of significance 
B)  value of   
C)  value of   
D)  sample size

Question 9

When a one-tailed test is employed (rather than a two-tailed test),

Accepted Answer

A)  t must be numerically larger to result in rejection of the null hypothesis 
B)  a less discrepant value of $\overline{X}$ may result in rejection of the null hypothesis 
C)  the level of significance should be changed 
D)  n should be inversed 
A)  t must be numerically larger to result in rejection of the null hypothesis 
B)  a less discrepant value of $\overline{X}$ may result in rejection of the null hypothesis 
C)  the level of significance should be changed 
D)  n should be inversed

Question 10

The answer to which of the following questions is the "key" to solving a statistical inference problem

Accepted Answer

A)  are the sample values close to the population values? 
B)  what sample values are likely to occur under random sampling? 
C)  is the sample sufficiently representative of the population to proceed? 
D)  is the sample large enough? 
A)  are the sample values close to the population values? 
B)  what sample values are likely to occur under random sampling? 
C)  is the sample sufficiently representative of the population to proceed? 
D)  is the sample large enough?

Question 11

Glo-lite light bulbs are advertised as having an average life of 600 hours with a standard deviation of 20. Consumer's Advocates (CA) has received numerous complaints that the bulbs burn out much more quickly. In order to check on the validity of these complaints, CA tests a sample of 25 bulbs and obtains: 
   
(a)Set up 
   
 and 
   
(b)Perform the statistical test (
   
(c)Draw final conclusions.?(d)?Now repeat using

Accepted Answer

(a)  
 
 @#IMG-DLM& (b)  
 @#IMG-DLM&

Question 12

The mean of the t distribution

Accepted Answer

A)  is   
B)  is the same as the mean of normally distributed z 
C)  varies with the size of the sample 
D)  varies with the distribution of scores from which it is derived 
A)  is   
B)  is the same as the mean of normally distributed z 
C)  varies with the size of the sample 
D)  varies with the distribution of scores from which it is derived

Question 13

We should probably use a lower value of   
than usual when

Accepted Answer

A)  n is small 
B)  we want to be quite confident that the null hypothesis should be rejected when we do so 
C)  we want to retain for further evaluation a possible (if not proven) difference 
D)  the test is directional 
A)  n is small 
B)  we want to be quite confident that the null hypothesis should be rejected when we do so 
C)  we want to retain for further evaluation a possible (if not proven) difference 
D)  the test is directional

Question 14

Ms. Phillips, research director of a large city school district, wishes to compare the mean score on a widely used reading readiness test of entering first graders in her district with the national norm of 62 and a standard deviation of 8. The results for a random sample of 10 children from her district are: 
   
(a) Set up 
   
 and 
 
  (b)Perform the statistical test (
 
  (c)Draw final conclusions.
(d)Now repeat using

Accepted Answer

(a)?
?
 @#IMG-DLM& (b)? 
 @#IMG-DLM& 
?(c)?retain

Question 15

If the outcome of a test is significant at the .05 level, it

Accepted Answer

A)  will be significant at the .01 level 
B)  will not be significant at the .01 level 
C)  may be significant at the .01 level 
D)  will probably not be significant at the .01 level 
A)  will be significant at the .01 level 
B)  will not be significant at the .01 level 
C)  may be significant at the .01 level 
D)  will probably not be significant at the .01 level

Question 16

Statistic:parameter as

Accepted Answer

A)  mean:standard deviation 
B)  sample:population 
C)  sample:mean 
D)  population:sample 
A)  mean:standard deviation 
B)  sample:population 
C)  sample:mean 
D)  population:sample

Question 17

The new Streamer four-cylinder compact is advertised as obtaining 39.2 miles per gallon (estimated highway mileage). A competitor doubts their claim and tests a sample of Streamers under highway conditions with the following results (in m.p.g.): 35, 41, 36, 32, 40, 38, 38, 36. Do these results cast doubt on the advertised claim?? 
(a)Set up 
   
 and

(b) Determine the critical value(s) of

(c)Perform the statistical test.
(d)Draw final conclusions.

Accepted Answer

(a)  
 @#IMG-DLM& 
 (b)  
 @#IMG-DLM& 
 
(c)  
 @#IMG-DLM&

Question 18

Which, if any, need not be decided in advance of conducting the test of a null hypothesis?

Accepted Answer

A)  the level of significance 
B)  the nature of   
C)  the region of rejection 
D)  all should be decided in advance 
A)  the level of significance 
B)  the nature of   
C)  the region of rejection 
D)  all should be decided in advance

Question 19

A one-tailed test should be used when

Accepted Answer

A)  there is reason to believe the outcome will point in a particular direction 
B)  the experimenter so chooses; it is a matter of personal preference 
C)  the outcome of a test is in a particular direction 
D)  there is no practical difference in meaning between finding that the null hypothesis is true and finding that a difference exists in a direction opposite to that stated in the directional alternative hypothesis 
A)  there is reason to believe the outcome will point in a particular direction 
B)  the experimenter so chooses; it is a matter of personal preference 
C)  the outcome of a test is in a particular direction 
D)  there is no practical difference in meaning between finding that the null hypothesis is true and finding that a difference exists in a direction opposite to that stated in the directional alternative hypothesis

Question 20

Compute the best estimates of 
   
and 
   
for each of the following samples:?
(a)pulse rate: 72, 86, 75, 66, 90;?
(b)number of tumors per rat: 2, 7, 8, 6, 6, 11, 3.

Accepted Answer

The answer of Compute the best estimates of 
 ...

For inference about single means, df is

If and and the critical values of z are when and when what would we do if our calculated value of z were -2.80?

We conduct a two-tailed test at the .05 significance level with data that afford 8 degrees of freedom. When we look up the critical value of t, we will expect it to be ____________ the corresponding critical value of z.

When the value of is changed from .05 to .01,

We are thinking of a two-tailed test, but decide on a one-tailed test. This means that

As the number of degrees of freedom increases, student's distribution of t

In general, "degrees of freedom" is most closely related to the

When a one-tailed test is employed (rather than a two-tailed test),

The answer to which of the following questions is the "key" to solving a statistical inference problem

The mean of the t distribution

We should probably use a lower value of than usual when

If the outcome of a test is significant at the .05 level, it

Statistic:parameter as

Which, if any, need not be decided in advance of conducting the test of a null hypothesis?

A one-tailed test should be used when

Compute the best estimates of and for each of the following samples:? (a)pulse rate: 72, 86, 75, 66, 90;? (b)number of tumors per rat: 2, 7, 8, 6, 6, 11, 3.

Introduction

Frequency Distributions, Percentiles,

Graphic Representation of Frequency Distributions

Central Tendency

Variability and Standard Z Scores

Standard Scores and the Normal Curve

Correlation

Prediction

Interpretive Aspects of Correlation and Regression

Probability

Random Sampling and Sampling Distributions

Interpreting the Results of Hypothesis Testing: Effect Size, Type I and Type II Errors, and Power

Testing Hypotheses About the Difference Between Two Independent Groups

Testing for a Difference

Inference About Correlation Coefficients

An Alternative to Hypothesis Testing: Confidence Intervals

Testing for Differences Among Three or More Groups: One-Way Analysis of Variance and Some Alternatives

Factorial Analysis of Variance

Chi-Square and Inference About Frequencies

Some Almost Assumption-Free Tests

Filters

Exam 12: Introduction to Statistical Inference: Testing Hypotheses About Single Means Z and T

For inference about single means, df is

If and and the critical values of z are when and when what would we do if our calculated value of z were -2.80?

We conduct a two-tailed test at the .05 significance level with data that afford 8 degrees of freedom. When we look up the critical value of t, we will expect it to be ____________ the corresponding critical value of z.

When the value of is changed from .05 to .01,

We are thinking of a two-tailed test, but decide on a one-tailed test. This means that

As the number of degrees of freedom increases, student's distribution of t

In general, "degrees of freedom" is most closely related to the

When a one-tailed test is employed (rather than a two-tailed test),

The answer to which of the following questions is the "key" to solving a statistical inference problem

The mean of the t distribution

We should probably use a lower value of than usual when

If the outcome of a test is significant at the .05 level, it

Statistic:parameter as

Which, if any, need not be decided in advance of conducting the test of a null hypothesis?

A one-tailed test should be used when

Compute the best estimates of and for each of the following samples:? (a)pulse rate: 72, 86, 75, 66, 90;? (b)number of tumors per rat: 2, 7, 8, 6, 6, 11, 3.

Introduction

Frequency Distributions, Percentiles,

Graphic Representation of Frequency Distributions

Central Tendency

Variability and Standard Z Scores

Standard Scores and the Normal Curve

Correlation

Prediction

Interpretive Aspects of Correlation and Regression

Probability

Random Sampling and Sampling Distributions

Interpreting the Results of Hypothesis Testing: Effect Size, Type I and Type II Errors, and Power

Testing Hypotheses About the Difference Between Two Independent Groups

Testing for a Difference

Inference About Correlation Coefficients

An Alternative to Hypothesis Testing: Confidence Intervals

Testing for Differences Among Three or More Groups: One-Way Analysis of Variance and Some Alternatives

Factorial Analysis of Variance

Chi-Square and Inference About Frequencies

Some Almost Assumption-Free Tests

Filters