Inferential Statistics

QUESTION 1

1. What do you call measurements of a subset of a population? 

		variable
		population
		statistics
		sample

5 points   

QUESTION 2

1. What is a graph with a great preponderance of high scores? 

		bimodal distribution
		normal distribution
		negative skew
		positive skew

5 points   

QUESTION 3

1. What is a number that conveys a particular characteristic of a set of data? 

		variable
		descriptive statistic
		inferential statistic
		nominal scale

5 points   

QUESTION 4

1. A friend brings you data that can be used to establish the independence of two variables. You run an analysis on the data and find a chi square value larger than the tabled value. Your analysis shows that the two variables

		are not independent
		neither answer is correct
		both answers are correct
		are independent

5 points   

QUESTION 5

1. Find the Chi-Square critical value for goodness of fit where alpha is the level of significance and k is the number of possible outcomes for each trial.

alpha (level of significance) =0.05 and k = 22, where degree of freedom = k - 1

		29.615
		32.671
		35.479
		41.401

5 points   

QUESTION 6

1. In a χ2 test of independence between gender and kinds of phobias, the null hypothesis was rejected. The proper conclusion is that

		knowing a person's phobia gives you no clue to his or her gender
		gender and phobias are independent of each other
		none of the choices are correct
		gender and phobias are related to each other

5 points   

QUESTION 7

1. The way in which the data analyzed with chi square differ from those analyzed with ANOVA is that chi square data are

		not random samples
		normally distributed
		frequency counts
		not normally distributed

5 points   

QUESTION 8

1. When contrasted with Pearson's correlation calculation, Spearman's correlation coefficient measures how well the data fits what assumption about the data? 

		That the data has a linear trend
		That the data is random
		That the data has an exponential trend
		That the data has a monotonic trend

5 points   

QUESTION 9

1. The general form of a null hypothesis for a Spearman correlation is:

		H0: There is a [monotonic] association between the two variables [in the population].
		H0: There is no [monotonic] association between the two variables [in the population].
		H0: There is an equal association between the two variables [in the population].
		H0: There is not an equal association between the two variables [in the population].

5 points   

QUESTION 10

1. Suppose you obtained a Spearman rs of .53 from a sample of 13 pairs of scores. For a two-tailed test, such a correlation coefficient is

		p < .05
		p <.001
		not statistically signficant
		p < .01

5 points   

QUESTION 11

1. Nonparametric tests are used rather than a t test or an ANOVA when

		the researcher does not know the specific value of the population parameters
		the assumption of random assignment is not justified
		a null hypothesis cannot be specified
		the data are in the form of ranks

5 points   

QUESTION 12

1. p < .05 means that the difference between sample means

		none of the choices are correct
		both choices are correct
		should be attributed to chance rather than to the independent variable
		the results should be declared "not significant";

5 points   

QUESTION 13

1. A researcher conducted a paired sample t-test to determine if advertisements were viewed more in the morning (before noon) or in the evening (after 5pm) for eight different universities.  The results were as follows: 

	Morning	Evening
	Morning	Evening
Mean	32	40.625
Variance	89.71428571	504.5536
Observations	8	8
Pearson Correlation	0.343785438
Hypothesized Mean Difference	0
df	7
t Stat	-1.152587077
P(T<=t) one-tail	0.143458126
t Critical one-tail	1.894578605
P(T<=t) two-tail	0.286916252
t Critical two-tail	2.364624252

Is there a significant difference between morning and evening access to the university advertisements?  

		No, there was no difference between Morning (M= 32), and Evening (M=40.625), (t [7] = 1.15, p > .05).
		No, there was no difference between Morning (M= 32), and Evening (M=40.625), (t [7] = 1.15, p < .05).
		Yes, there was a significant difference between Morning (M= 32), and Evening (M=40.625), (t [7] = .28, p < .05).
		Yes, there was a significant difference between Morning (M= 32), and Evening (M=40.625), (t [7] = 1.15 p < .05).

5 points   

QUESTION 14

1. Pearson product-moment correlation coefficients can accurately describe the relationship between two variables when

		all choices are correct
		the relationship between the two variables is curvilinear;
		the two variables are measuring different things;
		one of the variables has a truncated range;

5 points   

QUESTION 15

1. The null hypothesis in an ANOVA problem is that

		all the groups are drawn from the same population;
		one or more of the groups was drawn from a different population;
		any of the other alternatives, depending on how many levels of the independent variable there are.
		none of the groups were drawn from the same population;

5 points   

QUESTION 16

1. The one way ANOVA is not appropriate if the data come from

		populations that do not have the same mean
		neither choice is correct
		both choices are correct
		paired-samples design;

5 points   

QUESTION 17

1. For scores of 6, 3, 5, 6, 4, 4, 6, 5, the median is

		9
		5
		4
		4.5

5 points   

QUESTION 18

1. For scores of 8, 10, 8, 9, 8, 8, 9, 8, the median is 

		9
		4
		13.5
		8

5 points   

QUESTION 19

1. Over the past decade, ABC Manufacturing has increased the number of safety inspections per month in hopes to decrease the number accidents on their production line.  Below is a list of how many inspections were conducted in a month and the corresponding number of accidents recorded.  Is there a correlation, and has this leadership decision been effective?

Inspections	Accidents
20	181
24	190
28	167
40	160
60	120
64	124
64	118
68	90
70	94
72	85
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