Question 1

Which of the following is a quantitative variable?

Accepted Answer

Number of cars owned by a family

Question 2

A university wants to estimate the average time students spend searching for a parking spot. Which of the following best describes the sample in this scenario?

Accepted Answer

The students who responded to the survey about parking

Question 3

Given the following frequency table, calculate the mean value.

Value: 64 (frequency 3), 70 (frequency 12), 80 (frequency 7), 87 (frequency 7)

Which formula should be used?

Accepted Answer

$$\frac{\sum{(x_i \cdot f_i)}}{\sum{f_i}}$$

Question 4

A sample of 35 colleges yields the following enrollment numbers: 5100, 5200, 5300, ..., 7600. What is the formula for the sample mean?

Accepted Answer

$$\bar{x} = \frac{\sum{x_i}}{n}$$

Question 5

Which of the following best describes a histogram?

Accepted Answer

A graph that displays the distribution of quantitative data using adjacent bars

Question 6

Suppose you want to estimate the population mean using a large sample. Which confidence interval formula should you use if the population standard deviation $$\sigma is $$known?

Accepted Answer

$$\bar{x} \pm \left( z_{\alpha/2} \right) \left( \frac{\sigma}{\sqrt{n}} \right)$$

Question 7

A researcher wants to estimate the proportion of students who prefer online classes. The sample size is 100, and 60 students prefer online classes. What is the point estimate for the population proportion?

Accepted Answer

$$\hat{p} = \frac{60}{100} = 0.60$$

Question 8

Which technical condition must be met to use the large sample confidence interval for a population proportion?

Accepted Answer

$$n \cdot \hat{p} \geq 15$$ and $$n \cdot (1-\hat{p}) \geq 15$$

Question 9

Given the following boxplot of test scores, which value represents the median?

Accepted Answer

The value at the center of the box

Question 10

A student collects data on the number of hours spent studying and the final exam score. Which graph is most appropriate to display the relationship between these two variables?

Accepted Answer

Scatterplot

Question 11

If the sample mean is 75 and the sample standard deviation is 8, what is the z-score for a value of 91?

Accepted Answer

$$z = \frac{91 - 75}{8} = 2$$

Question 12

Which of the following is NOT a requirement for constructing a confidence interval for a population mean?

Accepted Answer

The population proportion must be known

Question 13

A real estate agent collects prices for 13 properties: $$120,000, 130,000, 140,000, 150,000, 160,000, 170,000, 180,000, 190,000, 200,000, 210,000, 220,000, 230,000, 500,000. $$Which value is a potential outlier using the IQR method?

Accepted Answer

$$500,000$$

Question 14

Which of the following best describes a qualitative variable?

Accepted Answer

A variable that can be classified into categories

Question 15

A survey asks students to report their favorite type of music. Which type of variable is this?

Accepted Answer

Qualitative

Question 16

Which formula is used to calculate the sample standard deviation?

Accepted Answer

$$s = \sqrt{\frac{\sum{(x_i - \bar{x})^2$}}{n-1}}$$

Question 17

A scatterplot shows a strong positive linear relationship between two variables. What does this indicate?

Accepted Answer

As one variable increases, the other tends to increase

Question 18

Which of the following is the formula for a large sample confidence interval for a population proportion?

Accepted Answer

$$\hat{p} \pm \left( z_{\alpha/2} \right) \sqrt{\frac{\hat{p}(1-\hat{p})}{n}}$$

Question 19

A manager rates employees according to job performance and attitude. Which statistical method is most appropriate to analyze the relationship between these two variables?

Accepted Answer

Correlation analysis

Comprehensive Study Notes: Descriptive and Inferential Statistics, Data Analysis, and Regression

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