Question 1

Jin predicts that people with highly symmetric faces will be rated as more attractive than people with less symmetric facial features.Is this hypothesis one- or two-tailed?

Accepted Answer

A)  two-tailed, because it is directional 
B)  two-tailed, because it indicates there will be a difference and the direction 
C)  one-tailed, because it only indicates there will be a difference but not the direction 
D)  one-tailed, because it is directional

Question 2

The statistical concept of p levels is often referred to as:

Accepted Answer

A)  betas. 
B)  alphas. 
C)  central tendency. 
D)  variability.

Question 3

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.Treating this class as the population, what percent of students study more than 13 hours a week? (Round z score to two decimal places.)

Accepted Answer

A)  15.91 
B)  24.83 
C)  25.17 
D)  34.09

Question 4

A z test result of 1.98 would allow one to reject the null hypothesis, assuming a two-tailed test with p = 0.05.

Accepted Answer

A) True 
 B)False

Question 5

The percentile is the:

Accepted Answer

A)  same thing as a percentage. 
B)  percentage of scores falling at or below a particular raw score. 
C)  percentage of scores falling at or above a particular raw score. 
D)  percentage of scores falling between a particular raw score and the mean.

Question 6

If 28 percent of scores fall between a negative z score and the mean, then 22 percent of scores fall below that z score.

Accepted Answer

A) True 
 B)False

Question 7

A given distribution has a mean of 50 and a standard deviation of 5.When comparing a score of 55 to this distribution of scores, the percentile rank is _____, whereas comparing a mean of 55, based on a sample of 10, to a distribution of means created from this parent population will result in a percentile rank of _____.

Accepted Answer

A)  1.00; 1.00 
B)  1.00; 3.16 
C)  3.16; 1.00 
D)  50.50; 55.10

Question 8

Assume the average height for American women is 64 inches with a standard deviation of 2 inches.What percent of groups of size 25 would have mean heights of more than 64.5 inches? (Round z score to two decimal places.)

Accepted Answer

A)  10.56 
B)  22.82 
C)  35.31 
D)  89.44

Question 9

If one rejects the null hypothesis, it means that the results of the study are important.

Accepted Answer

A) True 
 B)False

Question 10

One rejects the null hypothesis only when:

Accepted Answer

A)  the sample mean is larger than the population mean. 
B)  the p value associated with the test statistic is smaller than the p level chosen. 
C)  the sample mean is smaller than the population mean. 
D)  the p value associated with the test statistic is greater than the p level chosen.

Question 11

When attempting to find a percentage associated with a z score, the second step involves looking up:

Accepted Answer

A)  a raw score on the raw score table. 
B)  a standard score on the means table. 
C)  a z score on the z table. 
D)  the median to determine skewness.

Question 12

The sixth step in hypothesis testing is:

Accepted Answer

A)  calculating the test statistic 
B)  determining the characteristics of the comparison distribution. 
C)  selecting the appropriate test based on the population, comparison distribution, and underlying assumptions. 
D)  making a decision.

Question 13

Imagine that the mean height for all Division I women's basketball programs is 69 inches with a standard deviation of 3 inches.The 2010-2011 women's basketball team at the University of Connecticut, with 10 players listed on the roster, had an average height of 71.2 inches.Using the z statistic, what percent of means would fall below that for these UConn Huskies? (Round z score to two decimal places.)

Accepted Answer

A)  98.98 
B)  94.98 
C)  86.98 
D)  48.98

Question 14

Inferential statistical analyses that are based on a set of assumptions about the underlying population are:

Accepted Answer

A)  inaccurate. 
B)  permissible only when certain assumptions about the sample are met. 
C)  nonparametric tests. 
D)  parametric tests.

Question 15

If a result is statistically significant, then chance is said to account for the outcome.

Accepted Answer

A) True 
 B)False

Question 16

Because of the principle of _____, when sample sizes are at least 30, the distribution will most likely resemble a normal distribution.

Accepted Answer

A)  parametric statistics 
B)  nonparametric statistics 
C)  the central limit theorem 
D)  robustness

Question 17

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.The professor tells Mackenzie she scored at the 46th percentile.How many hours does she study per week? (Round z score to two decimal places.)

Accepted Answer

A)  0.10 hours 
B)  5.53 hours 
C)  9.47 hours 
D)  10.37 hours

Question 18

If we conduct the same study with different samples and get the same results each time, it is:

Accepted Answer

A)  more likely we have an error in our results. 
B)  more likely the results are accurate. 
C)  less likely the results are accurate. 
D)  less likely we can reject the null hypothesis.

Question 19

What proportion of a normal distribution corresponds to z scores less than 1.04?

Accepted Answer

A)  0.3508 
B)  0.1492 
C)  0.6492 
D)  0.8508

Question 20

If the percentage of scores falling between the mean and a z score of 0.30 is 11.79, then what is the percentage of scores falling between the mean and a z score of -0.30?

Accepted Answer

A)  11.79 
B)  -11.79 
C)  38.21 
D)  -38.21

Exam 7: Hypothesis Testing With Z Tests

Jin predicts that people with highly symmetric faces will be rated as more attractive than people with less symmetric facial features.Is this hypothesis one- or two-tailed?

The statistical concept of p levels is often referred to as:

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.Treating this class as the population, what percent of students study more than 13 hours a week? (Round z score to two decimal places.)

A z test result of 1.98 would allow one to reject the null hypothesis, assuming a two-tailed test with p = 0.05.

The percentile is the:

If 28 percent of scores fall between a negative z score and the mean, then 22 percent of scores fall below that z score.

Assume the average height for American women is 64 inches with a standard deviation of 2 inches.What percent of groups of size 25 would have mean heights of more than 64.5 inches? (Round z score to two decimal places.)

If one rejects the null hypothesis, it means that the results of the study are important.

One rejects the null hypothesis only when:

When attempting to find a percentage associated with a z score, the second step involves looking up:

The sixth step in hypothesis testing is:

Inferential statistical analyses that are based on a set of assumptions about the underlying population are:

If a result is statistically significant, then chance is said to account for the outcome.

Because of the principle of _____, when sample sizes are at least 30, the distribution will most likely resemble a normal distribution.

In one statistics course, students reported studying an average of 9.92 hours a week, with a standard deviation of 4.54.The professor tells Mackenzie she scored at the 46th percentile.How many hours does she study per week? (Round z score to two decimal places.)

If we conduct the same study with different samples and get the same results each time, it is:

What proportion of a normal distribution corresponds to z scores less than 1.04?

If the percentage of scores falling between the mean and a z score of 0.30 is 11.79, then what is the percentage of scores falling between the mean and a z score of -0.30?