EPIB300 Exam 2

The mean of a t-distribution is equal to _____.

0

t/f:If we fail to reject the null hypothesis at a significance level of α=0.05, then we also must fail to reject it at a significance level of α=0.10.

False. Suppose you got a p-value of 0.06, 0.06 is larger than α if α=0.05, so we fail to reject the null hypothesis. But 0.06 is less than α=0.10, thus we would reject the null hypothesis at a significance level of α=0.10.

t/f:When conducting a 2-sided one-sample Z test, the p value equals the P(|Z|>z)

False. The p value equals the 2*P(Z>|z|).

t/f:A small p-value (<0.01) provides evidence in support of the null hypothesis.

False. p-value <0.01 provides evidence to reject the null hypothesis.

Which of the following is correct concerning the definition of the MSB?

The MSB quantifies the variance of group means around the grand mean

t/f: Even though you rejected the null hypothesis, it may still be true

True. Under this situation, you made a type I error.

true/false: The p-value refers to the probability of the data or data more extreme assuming the null hypothesis is __________.

true

The p-value for a two-sided t-test is equal to:

twice the area under the curve to the right of the absolute value of the t-statistic.

rejection error

type I error

acceptance error

type II error

A t-test derives a p-value of 0.06. The p-value represents the probability that:

we would see the data or data that are more extreme assuming the null hypothesis is true.

This is the risk a researcher is willing to take in mistakenly rejecting a true null hypothesis

α

When conducting a one-sample test of significance, a t distribution is used when ___ is unknown.

σ

t/f:A p-value is the probability that the null hypothesis is true.

False. A p-value is the probability that you obtained as extreme or more extreme data (or, test statistic) given the null hypothesis is true. Note: "extreme or more extreme" in this definition refers to "far or further from the null hypothesis

For a sample of size 30, the degrees of freedom for a one-sample t test will be:

29 (n-1)

Which of the following is likely to result in a wider confidence intervals?

A large confidence level

Which of the following is TRUE about hypothesis testing?

A type II error occurs when there is difference but the null hypothesis is not rejected.

the hypothesis that declares a (nonrandom) difference between the observed results and the hypothesized value

Alternative hypothesis (HA)

family-wise error rate

As the number of comparisons being made increases, so does the type I error rate

true/false: For a 2-sided one-sample t test, the larger the absolute t statistic, the smaller the p value.

true

This statistical hypothesis contradicts the research hypothesis

Null hypothesis (H0)

Which of the following would result in a type I error for the null hypothesis that the average resting heart rate for individuals with pre-hypertension is 70 bpm and the alternative hypothesis that the average resting heart rate for individuals with pre-hypertension is not 70 bpm?

Reject the at the significance level of 0.05 based on the fact that the true 0Hpopulation average resting heart rate for individuals with pre-hypertension is 70 bpm.

The value of the population mean under the null hypothesis (µ0) comes from the __________

Research question

We take an SRS from a population and a separate SRS from another population. Which t procedure should we use?

a two-sample t test

Completing multiple hypothesis tests undermines the intention of restricting the number of type I errors advertised by the nominal ______ level

alpha

One-way ANOVA, when restricted to the comparison of means from two groups, is equivalent to a(n) _______ test.

equal variance independent t-test

The mean of all the observations combined in the data set is called the ______

grand mean

The sampling distribution of a mean will be approximately normal even when the population is not exactly normal as long as the sample is:

large

The statistic quantifies the variability of the group means around the grand mean.

mean square between

The variance within groups is estimated by the ______.

mean square within

Select the best test to use. A lab technician obtains a specimen of known concentration from a reference lab. She tests the specimen 10 times using an assay kit and compares the calculated mean to that of the known standard.

one sample t-test

A different technician compares the concentration of 10 specimens using 2 different assay kits. Ten measurements are taken with each kit. Results are then compared

paired sample t-test

true/false: As sample size increases, the t distribution more closely approximates the standard normal distribution.

true