Question 1

A researcher wants to estimate the average height of all students at a university. She randomly selects 100 students and calculates their average height. Which term best describes the average height calculated from these 100 students?

Accepted Answer

Statistic

Question 2

Which of the following is an example of data measured at the interval level?

Accepted Answer

Temperature in Fahrenheit

Question 3

A survey asks people to rate their satisfaction with a new product as 'poor', 'fair', 'good', or 'excellent'. What is the level of measurement for this data?

Accepted Answer

Ordinal

Question 4

Which sampling method is most likely to produce a biased sample?

Accepted Answer

Convenience sampling

Question 5

A Pareto chart is best used to:

Accepted Answer

Display categories in descending order to highlight the most frequent issues

Question 6

Which measure of center is most resistant to extreme outliers?

Accepted Answer

Median

Question 7

Given a data set with a mean of $$50$$ and a standard deviation of $$10$$, what is the $$z-$$score for a value of $$70$$?

Accepted Answer

$$z=2$$

Question 8

According to the Empirical Rule, what percentage of data falls within $$2$$ standard deviations of the mean in a normal distribution?

Accepted Answer

$$95\%$$

Question 9

If the probability of rain tomorrow is $$0.30$$, what is the probability that it will NOT rain?

Accepted Answer

$$0.70$$

Question 10

A bag contains $$5$$ red balls and $$7$$ blue balls. If you randomly select one ball, what is the probability it is red?

Accepted Answer

$$\frac{5}{12}$$

Question 11

A password consists of $$3$$ distinct letters. How many possible passwords can be formed from $$26$$ letters if order matters?

Accepted Answer

$$26	imes25	imes24$$

Question 12

In a binomial experiment with $$n=10$$ trials and probability of success $$p=0.4$$, what is the expected number of successes?

Accepted Answer

$$4$$

Question 13

A normal distribution has mean $$\mu=100$$ and standard deviation $$\sigma=15. $$What is the $$z-$$score for a value of $$130$$?

Accepted Answer

$$z=2$$

Question 14

According to the Central Limit Theorem, what happens to the distribution of sample means as the sample size increases (e.g., $$n \geq 30$$)?

Accepted Answer

It approaches a normal distribution

Question 15

A $$95\%$$ confidence interval for the mean is $$[42.1, 58.3]. $$What does this mean?

Accepted Answer

We are $$95\%$$ confident the true population mean is between $$42.1$$ and $$58.3$$

Question 16

Which of the following is the correct formula for the margin of error $$E$$ when estimating a population mean with known standard deviation $$\sigma$$?

Accepted Answer

$$E = z_{\alpha/2} \frac{\sigma}{\sqrt{n}}$$

Question 17

In hypothesis testing, which statement is TRUE about the null hypothesis $$H_0$$?

Accepted Answer

It always contains an equality sign ($$=$$, $$\leq$$, $$\geq)$$

Question 18

If the $$p-$$value in a hypothesis test is $$0.03$$ and the significance level $$\alpha is$$ $$0.05$$, what is the correct decision?

Accepted Answer

Reject $$H_0$$

Question 19

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

Accepted Answer

Rejecting $$H_0$$ when it is true

Question 20

If the correlation coefficient $$r$$ between two variables is $$-0.95$$, what does this indicate?

Accepted Answer

A strong negative linear relationship

Introductory Statistics: Comprehensive Study Guide (Chapters 1–10)

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드