Question 1

Which of the following best defines a point estimate?

Accepted Answer

A single value used to approximate a population parameter.

Question 2

A random variable $$X$$ represents the number of defective light bulbs in a box of 100. Is $$X$$ discrete or continuous?

Accepted Answer

Discrete, because $$X$$ can only take integer values.

Question 3

Which of the following is NOT a requirement for a probability distribution?

Accepted Answer

The sum of all probabilities must be greater than 1.

Question 4

Which symbol in the confidence interval formula represents the sample proportion?

Accepted Answer

$$\hat{p}$$

Question 5

Under what condition would a z-score be negative?

Accepted Answer

When the data value is less than the mean.

Question 6

Which of the following is a correct interpretation of a 99% confidence interval $$4.1 \u003c \mu \u003c 5.6$$?

Accepted Answer

We are 99% confident that the population mean $$\mu is $$between 4.1 and 5.6.

Question 7

Which of the following is a biased estimator?

Accepted Answer

Sample range as an estimator for population range.

Question 8

If you are asked to find the 85th percentile in a data set, you are being asked to find:

Accepted Answer

The value below which 85% of the data fall.

Question 9

Which of the following groups contains terms that can be used interchangeably?

Accepted Answer

Mean, expected value, average

Question 10

Which of the following does NOT describe the standard normal distribution?

Accepted Answer

It has a mean of 1 and a standard deviation of 0.

Question 11

Which formula gives the standard deviation $$\sigma$$ for a binomial distribution with parameters $$n$$ and $$p$$?

Accepted Answer

$$\sigma = \sqrt{np(1-p)}$$

Question 12

Suppose you want to find the probability that a standard normal random variable $$z is $$greater than 1.5. Which of the following steps is correct?

Accepted Answer

Find $$P(z \u003e 1.5) by $$looking up $$z = 1.5 in $$the standard normal table and subtracting the value from 1.

Question 13

Which of the following is the correct formula to convert a normal distribution $$X \sim N(\mu, \sigma) to a $$standard normal distribution $$Z$$?

Accepted Answer

$$Z = \frac{X - \mu}{\sigma}$$

Question 14

Which of the following best describes the Central Limit Theorem?

Accepted Answer

The sampling distribution of the sample mean approaches a normal distribution as the sample size increases, regardless of the population's distribution.

Question 15

A hospital administrator wants to estimate the proportion of patients who recover within a week. She selects a random sample of 100 patients. Which symbol represents the sample proportion?

Accepted Answer

$$\hat{p}$$

Question 16

Which of the following is NOT a characteristic of a binomial experiment?

Accepted Answer

The probability of success changes from trial to trial.

Question 17

Suppose a factory has 5 generators and the probability that any one generator fails is 0.1. What is the probability that at least one generator fails to operate?

Accepted Answer

$$1 - (0.9)^5$

Question 18

Which of the following is the correct formula for the mean $$\mu of a $$binomial distribution with parameters $$n$$ and $$p$$?

Accepted Answer

$$\mu = np$$

Question 19

The symbols $$z_{\alpha/2}$$ and $$t_{\alpha/2}$$ used in confidence interval formulas are called:

Accepted Answer

Critical values

Question 20

A researcher wants to know if the mean pulse rate of males is less than 70. She calculates a 95% confidence interval for the mean pulse rate as (68, 72). Can she justify the statement 'the mean pulse rate of males is less than 70'?

Accepted Answer

No, because 70 is within the confidence interval.

Step-by-Step Guidance for Statistics Exam Review (Chapters 5, 6, 7)

Guida di studio - Domande di pratica

Study guide - Flashcard