Question 13 1 pts A student in a class of 25 third grade students is described as having an IQ that is one standard deviation below the mean. If this student’s IQ is reported as a z-score, the corresponding z-score would be __________. Group of answer choices

-1

85

1

n – 1

Question 14 1 pts Although research questions typically attempt to generalize to a ________, a researcher typically examines data using a __________. Group of answer choices

sample, population

statistic, sample

population, sample

statistic, parameter

Question 15 1 pts A Pearson correlation of r = – .85 indicates that a scatter plot of the data would show __________. Group of answer choices

points clustered close to a regression line that slopes up to the right

points clustered close to a regression line that slopes down to the right

points widely scattered around a regression line that slopes up to the right

points widely scattered around a regression line that slopes down to the right

Question 16 1 pts A researcher might be interested in determining whether changes in social status are accompanied by changes in educational level.  Such researchers are attempting to discover whether there is a(an) ___________ between two or more variables. Group of answer choices

association

relationship

correlation

Each of the choices “a” through “c” are correct.

Question 17 1 pts

A researcher reports that there is a significant difference between two treatments at the .05 level of significance (alpha is .05). This means that __________. Group of answer choices

if the researcher repeated the experiment, there is a 95% chance that the same decision would be reached

the difference obtained in the experiment is at least 5% larger than the standard error

there is a 5% probability (or less) that the difference occurred simply by chance without any treatment effect the average score for one treatment is at least 5% higher than the average score for the other treatment

Question 18 1 pts

In general, increasing the alpha level (for example from .01 to .05) will __________. Group of answer choices

increase the likelihood of rejecting the null hypothesis

decrease the likelihood of rejecting the null hypothesis

increase the standard error

decrease the standard error

Question 19 1 pts

What is the shape of the distribution for the following set of scores:  1, 1, 2, 2, 2, 2, 2, 2, 3, 3, 4, 5, 6, 13, 25 Group of answer choices

symmetrical

positively skewed

negatively skewed

normally distributed

Question 20 1 pts An introductory statistics class has 9 freshman males, 15 freshman females, 8 sophomore males, and 12 sophomore females. What is the probability of randomly selecting a male from this group? Group of answer choices

9/24, or p = .375

8/20, or p  = .4

17/20, or p  = .85

17/44, or p =  .386

Question 21 1 pts

What is the mode for the following set of scores: : 1, 4, 6, 17, 4, 2, 3, 12, 7, 5, 9, 10, 3, 3, 6 Group of answer choices

3

4

6

6.5

Question 22 1 pts

The results of an independent-measures research study are reported as “t(35) = –2.12, p > .05”. What statistical decision was made? Group of answer choices

The researcher failed to reject the null hypothesis.

The null hypothesis was rejected.

There was a marginally significant effect of the treatment

The probability of a Type I error, or alpha error, is equal to -2.12.

Question 23 1 pts

For the past 20 years, the average high temperature on April 15th has been 82 degrees (Fahrenheit) with a standard deviation of 4 degrees.  This year the high temperature was 92 degrees on April 15th . Based on this information, this year’s temperature on April 15th was ______________. Group of answer choices

a little above average far

above average

above average, but it is impossible to describe how much above average

There is not enough information to compare last year with the average.

Question 24 1 pts

Which of the following research situations is most likely to use an independent two-sample t test design? Group of answer choices

Evaluate the effectiveness of a relaxation program for adult insomniacs by measuring how much time is spent sleeping before being taught relaxation training and again after 60 days of relaxation.

Evaluate the difference in quantitative skills between 7th grade males versus 7th grade females.

Evaluate the effectiveness of an arthritis medication by comparing pain levels in individuals before and after the medication.

Evaluate the height of children born prematurely when they become two years old and again when they reach three years old.

Question 25 1 pts

The power of a statistical test is the probability of __________. Group of answer choices

correctly rejecting a false null hypothesis

proving a true null hypothesis

correctly rejecting a false alternate hypothesis

proving a false null hypothesis

Question 26 1 pts

A researcher is curious about the average IQ of registered voters in the state of Texas. The entire group of registered voters in Texas is an example of a __________. Group of answer choices

statistic

population

sample

parameter

Question 27 1 pts

Which of the following research situations is most likely to use a two sample independent-measures design? Group of answer choices

Evaluate the effectiveness of a pain reliever by measuring how much pain is reduced after taking the medication.

Evaluate the effectiveness of a cholesterol medication by comparing cholesterol levels before and after taking the medication.

Evaluate the difference in self-esteem between student athletes and non-athletes.

Evaluate the development of verbal skills between age 2 years and age 3 years for a sample of girls.

Question 28 1 pts

The critical boundaries for a two-tailed one sample z test are z = +1.96 and –1.96. If the calculated z-score for the sample data is z = –1.8, then what is the correct statistical decision? Group of answer choices

reject the alternate hypothesis

reject the null hypothesis

fail to reject the alternate hypothesis

retain the null hypothesis