ISEE Middle Level Quantitative : How to find mean

Study concepts, example questions & explanations for ISEE Middle Level Quantitative

varsity tutors app store varsity tutors android store

Example Questions

Example Question #36 : Data Analysis

Find the mean of this set of numbers:

\(\displaystyle 879, 789, 978, 788, 789, 989, 899\)

Possible Answers:

\(\displaystyle 873\)

\(\displaystyle 789\)

\(\displaystyle 899\)

\(\displaystyle 875\)

\(\displaystyle 879\)

Correct answer:

\(\displaystyle 873\)

Explanation:

First add the numbers in the set: 

\(\displaystyle 879+789+978+788+789+989+899=6111\)

Then, divide by 7:

\(\displaystyle 6111\div 7=873\)

 

Example Question #37 : Data Analysis

Peter went fishing and caught 5 fish the first hour, 3 fish the second hour, and 4 the last hour. On average, how many fish did Peter catch per hour?

Possible Answers:

\(\displaystyle 12\)

\(\displaystyle 4\)

\(\displaystyle 5\)

\(\displaystyle 3\)

\(\displaystyle 6\)

Correct answer:

\(\displaystyle 4\)

Explanation:

First, add up the three numbers:

\(\displaystyle 5+3+4=12\)

Then, divide by 3, because there are three numbers in the data set:

\(\displaystyle 12 \div 3=4\)

Answer: On average, Peter caught 4 fish per hour.

Example Question #1 : How To Find Median

Consider the data set: \(\displaystyle \left \{ 13, 18, 20, 22, 24, 29, 30, 36\right \}\)

What is the difference between the mean of this set and the median of this set?

Possible Answers:

\(\displaystyle 1\)

\(\displaystyle 1.5\)

\(\displaystyle 0.5\)

\(\displaystyle 2\)

Correct answer:

\(\displaystyle 1\)

Explanation:

To get the mean, add the numbers and divide by 8:

\(\displaystyle \left ( 13+ 18+ 20+ 22+ 24+ 29+ 30+ 36 \right )\div 8 = 192 \div 8 = 24\)

To get the median, find the mean of the fourth- and fifth-highest elements (the ones in the middle):

\(\displaystyle (22 + 24) \div 2 = 46 \div 2 = 23\)

The difference is \(\displaystyle 24-23 = 1\)

Example Question #121 : Statistics & Probability

What is the mean of the values \(\displaystyle 34\), \(\displaystyle 40\), \(\displaystyle 1\), \(\displaystyle 9\)\(\displaystyle 21?\)

Possible Answers:

\(\displaystyle 5\)

\(\displaystyle 105\)

\(\displaystyle 40\)

\(\displaystyle 21\)

\(\displaystyle 34\)

Correct answer:

\(\displaystyle 21\)

Explanation:

The mean of a set of values can be calculated by adding the values together and dividing by the number of values: \(\displaystyle \frac{34+40+1+9+21}{5}=21\)

Example Question #563 : Isee Middle Level (Grades 7 8) Mathematics Achievement

Adrienne is trying on dresses for prom. The dresses she likes each cost \(\displaystyle \$129\), \(\displaystyle \$134\), \(\displaystyle \$127\) and \(\displaystyle \$132\), respectively. What is the average dress price that Adrienne is considering?

Possible Answers:

\(\displaystyle \$132.00\)

\(\displaystyle \$131.00\)

\(\displaystyle \$130.00\)

\(\displaystyle \$130.50\)

\(\displaystyle \$127.00\)

Correct answer:

\(\displaystyle \$130.50\)

Explanation:

First, add up all of the dress prices:

\(\displaystyle 129+134+127+132=522\)

Then, divide by the number of dresses:

\(\displaystyle 522 \div 4=130.50\)

Answer: The average dress price is \(\displaystyle \$130.50\)

Example Question #1721 : Grade 6

Find the mean of the data set provided:

Screen shot 2016 04 05 at 8.55.18 am

Possible Answers:

\(\displaystyle 30.55\)

\(\displaystyle 32.24\)

\(\displaystyle 31.6\)

\(\displaystyle 34.5\)

Correct answer:

\(\displaystyle 30.55\)

Explanation:

In order to answer this question correctly, we need to recall the definition of mean:

Mean: The mean of a data set is the average of the numbers in a data set. 

In order to calculate the mean we must first add up all of the numbers in the data set:

\(\displaystyle 28+30+31+26+34+26+36+33+34+35+34+32+28+30+34+26+27+30+28+29=611\) 

Next, we need to divide by the number of addends, or the number of numbers in the data set:

\(\displaystyle \frac{611}{20}=30.55\)

The mean for this data set is \(\displaystyle 30.55\)

Example Question #101 : Data Analysis And Probability

Find the mean, rounded to the nearest hundredth, of the data set provided:

Screen shot 2016 04 05 at 9.44.17 am

Possible Answers:

\(\displaystyle 16.87\)

\(\displaystyle 14.32\)

\(\displaystyle 17.43\)

\(\displaystyle 15.55\)

Correct answer:

\(\displaystyle 16.87\)

Explanation:

In order to answer this question correctly, we need to recall the definition of mean:

Mean: The mean of a data set is the average of the numbers in a data set. 

In order to calculate the mean we must first add up all of the numbers in the data set:

\(\displaystyle 15+27+22+14+20+20+11+21+13+14+19+18+14+11+14=253\) 

Next, we need to divide by the number of addends, or the number of numbers in the data set:

\(\displaystyle \frac{253}{15}=16.866...\)

The mean, rounded to the nearest hundredth, for this data set is \(\displaystyle 16.87\)

Example Question #1724 : Grade 6

Find the mean, rounded to the nearest hundredth, of the data set provided:


Screen shot 2016 04 05 at 10.03.05 am

Possible Answers:

\(\displaystyle 5.67\)

\(\displaystyle 6.83\)

\(\displaystyle 4.32\)

\(\displaystyle 7.03\)

Correct answer:

\(\displaystyle 5.67\)

Explanation:

In order to answer this question correctly, we need to recall the definition of mean:

Mean: The mean of a data set is the average of the numbers in a data set. 

In order to calculate the mean we must first add up all of the numbers in the data set:

\(\displaystyle 5+7+2+4+10+10+1+11+3+4+9+8+4+3+4=85\) 

Next, we need to divide by the number of addends, or the number of numbers in the data set:

\(\displaystyle \frac{85}{15}=5.66...\)

The mean, rounded to the nearest hundredth, for this data set is \(\displaystyle 5.67\)

Example Question #102 : Data Analysis And Probability

Find the mean of the data set provided:

Screen shot 2016 04 05 at 10.19.45 am

Possible Answers:

\(\displaystyle 5\)

\(\displaystyle 4.8\)

\(\displaystyle 7.3\)

\(\displaystyle 6\)

Correct answer:

\(\displaystyle 4.8\)

Explanation:

In order to answer this question correctly, we need to recall the definition of mean:

Mean: The mean of a data set is the average of the numbers in a data set. 

In order to calculate the mean we must first add up all of the numbers in the data set:

\(\displaystyle 2+7+2+4+1+8+4+9+3+4+9+8+4+3+4=72\) 

Next, we need to divide by the number of addends, or the number of numbers in the data set:

\(\displaystyle \frac{72}{15}=4.8\)

The mean for this data set is \(\displaystyle 4.8\)

Learning Tools by Varsity Tutors