Self-test Questions


1	What does the central limit theorem tell us?

		A)	That the sample mean is always the same.
		B)	That the sample mean tends to be normally distributed with mean μ and standard deviation σ / (√n)
		C)	That the population is normally distributed.
		D)	That the standard deviation of the sampling mean is the same as the population standard deviation.
		E)	That the sample mean always lies within 1.96 standard deviations of the population mean.

2	The null hypothesis is a statement that we set out to reject using a hypothesis test.

		A)	TRUE
		B)	FALSE

3	In order to set up a hypothesis test we set our null and alternative hypotheses and select a level of ________ for the test.

		A)	optimality
		B)	accuracy
		C)	variability
		D)	error
		E)	significance

4	When does a Type I error occur?

		A)	When we make a mistake in the calculation of the sample mean.
		B)	When we reject the null hypothesis even though it is true.
		C)	When we choose the wrong level of significance.
		D)	When we accept the null hypothesis when it is false.
		E)	When we formulate the null hypothesis incorrectly.

5	What sort of normal test requires a one-tailed test?

		A)	A test involving only one sample.
		B)	A test with an alternative hypothesis involving a ‘greater than’ or ‘less than’ relationship.
		C)	A test between two sample means.
		D)	A test with an alternative hypothesis involving an ‘equals’ relationship.
		E)	A test where the standard deviation of the sample is 1.

6	In using the student’s t distribution for a test involving a small sample, it is necessary to calculate the number of degrees of freedom before consulting the tables.

		A)	TRUE
		B)	FALSE

7	If our data comes from population of unknown distribution, we can use ________ tests.

		A)	normal
		B)	student’s t
		C)	geometric
		D)	parametric
		E)	non-parametric

8	The chi-squared distribution is symmetrical.

		A)	TRUE
		B)	FALSE

9	If we are carrying out a chi-squared test of association using a 3x3 contingency table, then how many degrees of freedom will there be?

		A)	4
		B)	9
		C)	10
		D)	3
		E)	8

10	The sampling distribution of the sample mean, has a mean of

		A)
		B)	σ
		C)
		D)	μ
		E)	s

11	What is the standard deviation of the sampling distribution of the sample mean,

		A)	σ / (√n)
		B)	σ
		C)	μ / n
		D)	σ / (n - 1)
		E)	(n - 1)σ

12	The standard deviation of the sample mean is always smaller than the standard deviation of x

		A)	TRUE
		B)	FALSE

13

		A)	z-value for μ
		B)	Hypothesis test for μ
		C)	95% confidence interval for μ
		D)	Measure of the standard deviation of μ
		E)	Formula for the sampling distribution of μ

14	If n is less than 30 it is necessary to use the ________ distribution to calculate confidence intervals for μ

		A)	normal
		B)	exponential
		C)	student’s t
		D)	binomial
		E)	Poisson

15	If the value of is 1.96 then the standard error of the sample mean is 1.96.

		A)	TRUE
		B)	FALSE

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