A study recorded the time (in minutes) spent on daily exercise by a group of 50 individuals. The collected data was summarized into the following frequency distribution:

Compute the mean of the data summarized in the frequency distribution.

Compare the computed mean to the actual mean obtained from the original list of data values, which is 31.2 minutes.

A study found a linear correlation between the number of household appliances and the monthly electricity usage. The relationship is modeled by the regression equation $\hat{y}=50.8+12.4x$, where $x$ represents the number of household appliances, and $\hat{y}$ represents the predicted monthly electricity usage in kilowatt-hours ($\text{kWh}$). What is the predicted electricity usage for a home with $9$ appliances?

A group of hobbyists recorded the number of minutes they spent gardening on a given day. The data collected is grouped into the following frequency distribution:

Approximate the mean number of minutes spent gardening.

Listed below are the number of books borrowed from a library by $8$ individuals.

a. What is the mean of the number of books borrowed?

b. What is the median of the number of books borrowed?

The following are the systolic blood pressure readings (in $\text{mmHg}$) for a group of $10$ male patients:

$122$, $138$, $145$, $130$, $154$, $127$, $142$, $136$, $150$, $134$.

Find the mean, median, and mode of the data. If any measure cannot be found or does not represent the center of the data, explain why.

The times (in minutes) it took nine students to complete a quiz are $18$, $22$, $15$, $25$, $20$, $16$, $19$, $24$, and $21$. What are the mean and median times?

A student's math test score is converted into a z-score. Which of the following z-scores would the student prefer: $\text{-1.5, -0.5, 0, 1.5, 2.5}$?

A college surveyed students about the number of books they read for leisure in a semester. The results are grouped as follows:

Estimate the sample mean and sample standard deviation. Use $10$ as the midpoint for the '$9+$ books' group.

The number of hours five employees worked in a week is as follows: $32$, $36$, $40$, $44$, $48$. What is the sample standard deviation of the hours worked? Use the formula $s=\sqrt{\frac{\sum x^2-\frac{{(\sum x)}^2}{n}}{n-1}}$.

Listed below are the self-reported weights (in kilograms) of adults and their corresponding measured weights, based on data from a national health survey.

Compute the differences (self-reported weight – measured weight).

Use these differences to construct a boxplot and include the values of the 5-number summary.

Consider the following set of test scores. Find the interquartile range: $68,72,65,70,69,74,70,71,67,73,80,72,70,75,77$