Which of the following is a fundamental difference between the t and z statistic?

Select one:

a.

The z-statistic requires the population standard deviation () and the t-statistic doesn't

b.

The t-statistic allows for lower sample size due to degrees of freedom

c.

The t-statistic requires a normal distribution and the z-statistic doesn't

d.

The z-statistic requires the population mean () and the t-statistic doesn't

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The sample variance (s2) for a sample of n = 25 with a SS = 2400 is equal to

Select one:

a.

96

b.

100

c.

10

d.

There is not enough information to calculate sample variance.

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The standard error (sM) for a sample of n = 16 with a SS = 960 is equal to

Select one:

a.

2

b.

There is not enough information to calculate the standard error.

c.

16

d.

64

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Use the following study to answer questions 4-6.To demonstrate the Flynn effect (the notion that IQ scores increase with every generation), a researcher obtains an old IQ test (assume normally distributed)with a population mean = 100.The researcher administers the test to a random sample of n = 16 of today's high school students and obtains a sample mean of M = 121 with a SS = 6000.Use a one-tailed test with = .01.

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What is the critical value for the t-test and what side of the distribution is it on?

Select one:

a.

2.947, right

b.

2.947, left

c.

2.602, right

d.

2.602, left

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What is the obtained t-statistic?

Select one:

a.

4.07

b.

There is not enough information to calculate a t-statistic

c.

4.34

d.

4.20

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Are the results sufficient to conclude that today's sample scored significantly higher than the population mean?

Select one:

a.

Yes, there is enough evidence to reject the null and conclude that the sample mean was significantly higher than the population mean.

b.

No, we should fail to reject the mean.There is not enough evidence to conclusively state that the sample mean was significantly higher than the population mean.

c.

There is not enough evidence to make any conclusions about statistical significance.

d.

Yes, we can reject the null hypothesis, but the risk of a Type II error is too high to make any conclusive statements about the means.

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Evidence has suggested an increase in measures of anxiety over the past seventy years.In the 1950's, the average indicator of anxiety was = 15.1.A sample of n = 16 of today's children produces a mean score of M = 23.3 with s = 1.What is the 90% confidence interval used to estimate the mean level of anxiety?

Select one:

a.

21.58 to 25. 05

b.

There is not enough information to calculate a confidence interval

c.

21.96 to 24.64

d.

23.18 to 23.42

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Which of the following is an example of a dependent sample t-test?

Select one:

a.

Comparing the self-esteem of 30 schoolchildren at 2 different schools within the same school district.

b.

Comparing accident history of men and women

c.

Comparing performance scores of 9thand 10thgrade adolescents

d.

Comparing achievement scores before and after a tutoring session

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Which of the following is the correct alternative hypothesis for an Independent samples t-test?

Select one:

a.

M1-M2 0

b.

M1-M2= 0

c.

1- 2= 0

d.

1- 2 0

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What is the correct description of a research study comparing sharing behaviors obtained for 3 separate and distinct groups of children?

Select one:

a.

Two factor ANOVA

b.

Onefactor ANOVA

c.

Factorial design

d.

Three factor ANOVA

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In an ANOVA test, when the null hypothesis is true, we would expect the F-ratio to be

Select one:

a.

Less than 1.0

b.

Greater than 1.0

c.

Equal to 0.0

d.

Equal to 1.0

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Post-tests (Pairwise comparisons) are necessary when doing an ANOVA when

Select one:

a.

The null hypothesis is rejected and there are more than two levels being compared

b.

We fail to reject the null hypothesis and there are more than two levels being compared

c.

The null hypothesis is rejected and there are two levels being compared

d.

We fail to reject the null hypothesis and there are two levels being compared