Q: Which of the following is the correct symbolic form for the null and alternative hypotheses for testing if a new drug has a different mean effect than the standard ($$\mu_0$)?

$$H_0$$: \mu = \$$mu_0$$, $$H_a: \mu \neq \mu_0$

Question 1

A 95% confidence interval for the difference in means between two populations is given as $$(-2.1, 4.3). $$What does this interval suggest about the difference in the two population means?

Accepted Answer

There is no significant difference between the two population means at the 95% confidence level.

Question 2

Which of the following is NOT part of the 5-number summary of a data set?

Accepted Answer

Mean

Question 3

Given a data value $$x = 85$$, a mean $$\mu = 70$$, and a standard deviation $$\sigma = 5$$, what is the $$z-$$score, and is this value significant at the 5% level (using $$|z| \u003e 1.96 as $$the cutoff)?

Accepted Answer

$$z = 3.0$$, which is significant.

Question 4

Which of the following best defines a parameter in statistics?

Accepted Answer

A numerical measurement describing a characteristic of a population.

Question 5

A grouped frequency distribution table has classes: 10-19, 20-29, 30-39, 40-49. What is the class width?

Accepted Answer

$$10$$

Question 6

Which of the following is a correct symbolic representation for testing the claim 'the mean is greater than 50'?

Accepted Answer

$$H_0$$: \mu = 50$$, H_a$$: \mu \u003e 50$$

Question 7

Which of the following is NOT a type of probability distribution?

Accepted Answer

Rectangular distribution

Question 8

A researcher wants to estimate the average cholesterol level in adults. She divides the city into neighborhoods and randomly selects several neighborhoods, then surveys all adults in those neighborhoods. What type of sampling is this?

Accepted Answer

Cluster sampling

Question 9

Which of the following statements about correlation is TRUE?

Accepted Answer

A correlation coefficient close to $$0$$ indicates little or no linear relationship between variables.

Question 10

Which of the following is a Type I error in hypothesis testing?

Accepted Answer

Rejecting the null hypothesis when it is actually true.

Question 11

A hospital administrator wants to know if the average wait time in the emergency room is different from 30 minutes. Which type of hypothesis test should be conducted?

Accepted Answer

Two-tailed test

Question 12

If a hypothesis test leads to rejecting the null hypothesis, what is the correct nontechnical conclusion?

Accepted Answer

There is sufficient evidence to support the alternative claim.

Question 13

Which of the following is the correct symbolic form for the null and alternative hypotheses for testing if a new drug has a different mean effect than the standard ($$\mu_0$)?

Accepted Answer

$$H_0$$: \mu = \$$mu_0$$, $$H_a: \mu 
eq \mu_0$

Question 14

Which of the following best describes mutually exclusive events?

Accepted Answer

Events that cannot occur at the same time.

Question 15

Given the data set: $$3, 7, 8, 12, 15$$, what is the median?

Accepted Answer

$$8$$

Question 16

If the $$z-$$score for a value is $$1.25$$, what is the area to the left of this $$z$$ value (rounded to two decimal places)?

Accepted Answer

$$0.89$$

Question 17

For a data set of home prices with several large outliers, which of the following is most likely true?

Accepted Answer

The mean will be greater than the median.

Question 18

A coin is tossed 5 times. How many possible outcomes are there?

Accepted Answer

$$2^5 = 32$

Question 19

The regression line equation should be used to predict $$y$$ values for given $$x$$ values only if:

Accepted Answer

The $$x$$ value is within the range of observed data.

Question 20

If the variance of a data set is $$16$$, what is the standard deviation?

Accepted Answer

$$4$$

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