Stat Unit 3

Increasing the sample size while keeping the confidence level the same will result in a narrower confidence interval.

True

The confidence level is the proportion of all possible samples for which the confidence interval will cover the true value.

True

When presenting the results of a hypothesis test, one should report the p-value or the value of the test statistic.

True

When testing a hypothesis for a proportion, the alternate hypothesis is always two-tailed.

False

If we decrease the value of the significance level a, we ____ the probability of a Type 1 error.

decrease

To test H0: p=p) with the methods in this section, the values np0 and n(1-p0) must both be atleast

10

To use the method of this section (proportions) to test a hypothesis about the difference between two proportions, each sample must contain at least ___ individuals in each category.

10

When constructing a confidence interval for a population mean u from a sample size of 12, the number of degrees of freedom for the critical value is _____.

11

To use the method of this section (proportions) to test a hypothesis about the difference between two proportions, each population must be at least ___ times as large as the sample drawn from it.

20

A contingency table containing observed values has three rows and four columns. The number of degrees of freedom for the chi-square statistic is 7.

False

A t-test is used when the number of degrees of freedom is unknown.

False

H1: u>50 is an example of a left-tailed alternate hypothesis test

False

If a 95% confidence interval for a population mean is 1.7<u<2.3, then the probability is .95 that the mean is between 1.7 and 2.3.

False

If the p-value is very small, we can be sure that the results have practical significance.

False

If we do not reject H0, then we conclude that H0 is true.

False

If we do not reject H0, then we conclude that H1 is false.

False

In the test of homogeneity, the alternate hypothesis says that the distribution in the rows are the same.

False

The individuals in each sample are divided into three or more categories.

False

The margin of error does not depend on the sample size.

False

The probability of a Type 2 error is a, the significance level.

False

The students t curve is less spread out than the standard normal curve.

False

To construct a confidence interval for a population mean, we add and subtract the critical value from the point estimate.

False

To use the methods of this section to test a hypothesis about the difference between two means, the population standard deviations must be known.

False

If we estimate the necessary sample size and no value for p(hat) is available, the estimated sample size will be larger than if a value for p(hat) were available.

True

The procedure for testing homogeneity is the same as the procedure for testing independence.

True

The smaller the p-value, the stronger the evidence against H0.

True

The students t distribution should not be used to find a confidence interval for u if outliers are present in a small sample.

True

When testing a hypothesis for a proportion, we assume that the items in the population are divided into two categories.

True

Rejecting H0 when it is true is called a ____ error, and failing to reject H0 when it is false is called a ____ error.

Type 1, Type 2

We reject H0 if the value of the test statistic is ___ the critical value.

greater than or equal to

In the test for ____, the null hypothesis is that distribution of the column variable is the same in each row.

homogeneity

If the sample sizes are n1 and n2, the simplest way to compute the degrees of freedom is to use the smaller of ___ and ____.

n1-1 and n2-2

The smaller the p-value is, the stronger the evidence against the ____ hypothesis becomes.

null

The ______ hypothesis states that a parameter is equal to a certain value while the ____ hypothesis states that the parameter differs from this value.

null, alternative

A single number that estimates the value of an unknown parameter is called a _____ estimate.

point

To perform a t-test when the sample size is small, the sample must show no evidence of strong ___ and must contain no _____.

skewness, outliers

To use the methods of this section to test a hypothesis about the difference between two means when the samples are small, the samples must show no evidence of strong ____ and must contain no_____.

skewness, outliers

To estimate the necessary sample size when no value of p(hat) is available, we use p(hat)=

.5

To test H0: p=p0 with the methods in this section, the population size must be at least ______ times as large as the same size.

20

The p-value represents the probability that H0 is true

False

To calculate the expected frequencies, we must know the row totals, column totals, and the _____ total.

Grand

The ____ is the probability, assuming H0 is true, of observing a value for the test statistic that is as extreme as or more extreme than the value actually observed.

P-value

In general, it is not recommended to use a pooled standard deviation when testing a hypothesis for the difference between means.

True

A t-test is used when the population standard deviation is unknown.

True

If the p-value is less than the significance level, we reject H0.

True

If we reject H0, we conclude that H0 is false.

True

To compute the test statistic, it is necessary to compute the pooled proportion.

True- but I thought she said to always put "NO" in the calculator

When using the critical value method, the region that contains the unusual values is called the ____ region.

critical

The margin of error is the product of the standard error and the ________.

critical value

If we decrease the value of the significance level a, we ____ the probability of a Type 2 error.

increase

If we increase the confidence level and keep the sample size the same we ______ the margin of error.

increase

In the confidence interval 24.3 +- 1.2, the quantity 1.2 is called the

margin of error

When the number of degrees of freedom is large, the students t distribution is close to the _____ distribution.

normal

When results are statistically significant, they do not necessarily have _____ significance.

practical

The number of degrees of freedom for the students t-test of a population mean is always 1 less than the ____.

sample size