Question 1

Which of the following best describes the difference between a population and a sample?

Accepted Answer

A population includes all individuals of interest, while a sample is a subset of the population.

Question 2

Which of the following is an example of a qualitative variable?

Accepted Answer

The color of cars in a parking lot.

Question 3

A researcher wants to study the effect of a new drug on blood pressure. She randomly assigns patients to receive either the drug or a placebo. What type of study is this?

Accepted Answer

Experimental study

Question 4

Which sampling method is used when every member of the population has an equal chance of being selected?

Accepted Answer

Simple random sampling

Question 5

Given the following data set: 2, 4, 4, 6, 8, what is the mean?

Accepted Answer

$$ \frac{2+4+4+6+8}{5} = 4.8 $$

Question 6

Which of the following is NOT a measure of central tendency?

Accepted Answer

Range

Question 7

A data set has a mean of 50 and a standard deviation of 5. What is the z-score for a value of 60?

Accepted Answer

$$ z = \frac{60-50}{5} = 2 $$

Question 8

Which of the following best describes a histogram?

Accepted Answer

A graph that displays data using bars of equal width to represent frequencies of classes.

Question 9

If the median is greater than the mean in a data set, the distribution is most likely:

Accepted Answer

Negatively skewed (left-skewed)

Question 10

Which formula is used to calculate the variance $$ s^2$  of a $$sample?

Accepted Answer

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

Question 11

A boxplot is useful for identifying which of the following?

Accepted Answer

Outliers in the data

Question 12

Which of the following is a correct interpretation of the 75th percentile in a data set?

Accepted Answer

25% of the data values are above this value.

Question 13

A researcher collects data on the number of hours students study per week and their exam scores. Which graph is most appropriate to display the relationship between these two variables?

Accepted Answer

Scatterplot

Question 14

Which of the following is a characteristic of a normal distribution?

Accepted Answer

It is symmetric and bell-shaped.

Question 15

If a data set has the following five-number summary: Min = 10, Q1 = 20, Median = 30, Q3 = 40, Max = 50, what is the interquartile range (IQR)?

Accepted Answer

$$ IQR = Q3 - Q1 = 40 - 20 = 20 $$

Question 16

Which of the following best describes the purpose of using a frequency distribution table?

Accepted Answer

To organize data into classes and show the frequency of each class.

Question 17

A researcher wants to estimate the average height of all university students. She selects 10 students from each department. What type of sampling is this?

Accepted Answer

Stratified sampling

Question 18

Which of the following is the correct formula for the coefficient of variation (CV) for a sample?

Accepted Answer

$$ CV = \frac{s}{\bar{x}} 	imes 100\% $$

Question 19

Which of the following is a potential source of bias in a survey?

Accepted Answer

Ensuring all participants are from the same neighborhood.

Question 20

If the range of a data set is 24 and the minimum value is 10, what is the maximum value?

Accepted Answer

$$ 24 + 10 = 34 $$

Math 2193 - Elementary Statistics: First Exam Review Study Notes

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