MO MAP Algebra I Statistics and Probability. Practice it free.

A grocer surveyed $25$ customers selected at random and found that $15$ of them purchased at least one organic item. Based on the survey, which of the following is the best estimate of the number of customers out of $500$ who would purchase at least one organic item?

A survey recorded the number of text messages sent per day. Which group has the greatest standard deviation?

Group A: $50, 50, 50, 50, 50$
Group B: $40, 45, 50, 55, 60$
Group C: $48, 49, 50, 51, 52$
Group D: $30, 50, 50, 50, 70$

The practice times, in minutes, for five days are $18\textsf{,}$ $22\textsf{,}$ $30\textsf{,}$ $20\textsf{,}$ and $35\textsf{.}$ Which data set has the same mean?

Five quiz scores are $92\textsf{,}$ $68\textsf{,}$ $75\textsf{,}$ $88\textsf{,}$ and $77\textsf{.}$ Which data set has the same median?

During a fitness challenge, four teammates completed $15$, $20$, $18$, and $22$ push-ups in the first four rounds. In the fifth round, one teammate completed $x$ push-ups. The mean number of push-ups per round is $19$. What is the value of $x$?

A box plot summarizes the data 1, 3, 3, 5, 8, 8, 10, 12. Find the median.

A science lab uses a random molecule selector. A fixed-width release bar is divided into $4$ chamber gates that should release molecules equally often. After $500$ selections, the counts were:

| Chamber | Selections |
| :-- | --: |
| A | $128$ |
| B | $82$ |
| C | $127$ |
| D | $163$ |

Which change would most likely make the selector fair?

Quiz scores are approximately normally distributed with mean $80$ and standard deviation $4$. By the empirical rule, about what percent of scores are between $72$ and $88$? (Enter the number of percent.)