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 mean must be equal to the median.

Question 4

Which symbol is used in confidence interval formulas to represent the sample proportion?

Accepted Answer

$$\hat{p}$$

Question 5

Suppose the mean pulse rate of males is 72 with a 95% confidence interval of (70, 74). Can we use this interval to justify the statement: "the mean pulse rate of males is less than 70"?

Accepted Answer

No, because 70 is the lower bound of the interval, not below it.

Question 6

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

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

The sample range as an estimator for population range.

Question 8

If you are asked to find the 85th percentile in a normal distribution, you are being asked to find:

Accepted Answer

The value below which 85% of the data falls.

Question 9

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

Accepted Answer

Sample mean, point estimate, unbiased estimator

Question 10

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

Accepted Answer

It is skewed to the right.

Question 11

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

Accepted Answer

$$\sigma = \sqrt{npq}$$

Question 12

A random variable $$Z$$ has a standard normal distribution. How would you find $$P(Z \u003e 1.5)$$?

Accepted Answer

Find the area to the right of $$z = 1.5$$ using the standard normal table.

Question 13

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 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

Which of the following procedures results in a binomial distribution?

Accepted Answer

Counting the number of heads in 10 flips of a fair coin.

Question 16

Which of the following symbols is used for the critical value in a confidence interval formula?

Accepted Answer

$$z_{\alpha/2}$$

Question 17

A random variable $$Y$$ represents the amount of rainfall in a city in a day (in inches). Is $$Y$$ discrete or continuous?

Accepted Answer

Continuous, because rainfall can take any value within a range.

Question 18

What is the probability that at least one generator fails to operate if the probability that a generator operates is 0.98 and there are 5 generators?

Accepted Answer

$$1 - (0.98)^5$

Question 19

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

Accepted Answer

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

Question 20

Which of the following best describes a density curve?

Accepted Answer

A curve that describes the overall pattern of a distribution and has area equal to 1.

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

Guida di studio - Domande di pratica

Study guide - Flashcard