Question 1

Which of the following best describes the process of using a measurement from a sample to draw a meaningful conclusion about a population?

Accepted Answer

Statistical inference

Question 2

In hypothesis testing, which hypothesis always contains an equal sign ("=")?

Accepted Answer

The null hypothesis

Question 3

If the p-value is greater than the significance level $$\alpha$$, what should you do regarding the null hypothesis?

Accepted Answer

Fail to reject the null hypothesis

Question 4

A friend claims they can make a fair six-sided die land on an even number more than 50% of the time. What is the correct null hypothesis for this scenario?

Accepted Answer

$$H_0$$: p = 0.50$$

Question 5

In the same die scenario, what is the correct alternative hypothesis?

Accepted Answer

$$H_a: p \u003e 0.50$$

Question 6

If an observed value has a very small p-value, what does this indicate about the null hypothesis?

Accepted Answer

It discredits the null hypothesis

Question 7

A group of 1600 elderly people were surveyed, and 350 said they use Instagram. We are testing if more than 20% use Instagram. The z-test statistic is 1.88. The p-value is 0.030. If the significance level is 0.05, what is the correct conclusion?

Accepted Answer

Because the p-value is less than the significance level, we reject the null hypothesis.

Question 8

In a poll of 700 Orlando residents, 370 support a traffic improvement idea. What is the sample proportion $$\hat{p}$$?

Accepted Answer

$$\hat{p} = 0.529$$

Question 9

Given the scenario above, what are the null and alternative hypotheses?

Accepted Answer

$$H_0$$: p = 0.50$$, H_a$$: p \u003e 0.50$$

Question 10

A recent poll found that 641 out of 985 adults would take an adults-only Disney vacation. What is the sample proportion $$\hat{p} ($$rounded to one decimal place)?

Accepted Answer

$$\hat{p} = 0.651$$

Question 11

In a two-sample proportion test, if $$z = 1.24$$ and $$p-$$value = 0.108, and the significance level is 0.05, what is the correct decision?

Accepted Answer

Fail to reject the null hypothesis

Question 12

When creating a confidence interval, we add and subtract the margin of error to our ________.

Accepted Answer

statistic or estimator

Question 13

A person weighs four bags of candy labeled '5 pounds' and finds weights of 4.9, 4.5, 4.7, and 4.75 pounds. The 95% confidence interval for the mean weight is (4.45, 4.98). What does this interval suggest about the seller's claim?

Accepted Answer

There is enough evidence to show the seller is lying about the average weight.

Question 14

A sample of 20 math students watched an average of 5.75 episodes of 'Ask the Storybots' per week. The population mean is 4.5. What is the correct null hypothesis for testing if math students watch more episodes?

Accepted Answer

$$H_0$$: \mu = 4.5$$

Question 15

If a confidence interval for the difference of two population means contains zero, what does this indicate?

Accepted Answer

The population means may be the same

Question 16

Refer to the first image. What does this image represent in the context of hypothesis testing?

Accepted Answer

The standard normal distribution with no area shaded, representing no rejection region.

Question 17

Refer to the second image. What does the shaded region represent in the context of hypothesis testing?

Accepted Answer

The p-value for a right-tailed test

STA 2023 Ch 8-9 Test Review: Hypothesis Testing, Confidence Intervals, and Proportions

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