# Mean - practice problems

the arithmetic mean (simply the mean or average) is the sum of a collection of numbers divided by the count of numbers in the collection. The arithmetic mean is the most commonly used and readily understood measure of central tendency in a data set. It is a statistical characteristic of the center of a given data set.Arithmetic mean is a quantity very sensitive to extreme values, so the median and mode are also used in practice. Mode is the most common value. The median halves the ordered file.

#### Number of problems found: 634

- Find mean

Find mean of two numbers: -4 and 5 (first is negative four). - The median 2

Here is a list of numbers: 9.9, 5.9, 3.6, 6.2, 8.9, 0.7, 4.4, 6.7, 9.9, 0.7 State the median. Give your answer as a decimal. - The average 12

The average of the first five numbers drawn was 2499. the first four numbers were 4165, 320, 7142, and 64. What was the fifth number? - The mean 2

The mean cost of 4 items was $39.96. The first item cost $28.50, the second item cost $41.25, and the third item cost $50. Find the cost of the fourth item. - Correct mean and CV

For a group of 100 students, the mean and coefficient of variation of their marks were found to be 60 and 25, respectively. Later, it was found that the scores 45 and 70 were wrongly entered as 40 and 27. Find the corrected mean and coefficient of variati - IQ scores

IQ scores are normally distributed with a mean of 100 and a standard deviation of 15. What percentage of the population scores higher than 125 on an IQ test? - The endpoints

The endpoints of a segment are (-6,1) and (10,11). What are the coordinates of its midpoint? - The usage

The battery usage time installed in a particular smartphone has a Normal distribution with a mean of 25.2 hours and a standard deviation of 7.5 hours. What is the probability of usage time greater than 32? - Squared deviation

Given the data from the problem (sample data: 23, 27, 35, 44), find the sum of the squared deviations (the numerator of the fraction under the square root in the formula). In finding the number, round all calculations to 2 decimals (if you carry more or f - Variance formula

Find the variance of 10,10,10,20,20,30. - Below 5

Below is a collection of test scores from a class of 20 students. Make 2 histograms of the data. Choose your own horizontal scales as long as you have more than 4 cells in each histogram. 65 70 68 87 98 91 77 85 70 72 86 86 94 95 67 88 77 99 74 71 - Geometric 20

Find the geometric mean of 15 15 20 25 30. - The average 11

The average of a set of 7 numbers is 20. The average of a second set of 13 numbers is 40. What is the mean of all 20? - The median (odd)

Janaiah's grades in her third periodical tests are 98, 97, 86, 94, 90, 97, 91, and 94. Find the median of her grades and interpret the result. - The average 10

The average of three fractions is 2 3/8. If two of the fractions are 2 1/5 and 1 2/3, what is the total value of the three fractions? - The number 9

The number of minutes it took Jim to ride his bike to school for each of the past six days was 21, 18, 16, 19, 24, and 19. Find the mean number of minutes. - Kenji

Kenji earned the test scores below in English class. {79, 91, 93, 85, 86, and 88} After his next test, his mean and median scores both changed to 88. What does he earn on his test? - Two classes

The average of 1A class of 25 is 12 years, and the average age of 1B class of 22 is 10 years. What is the average age of the pupils of 1A and 1B classes? - A meteorologist

A meteorologist calculated that the average temperature over the last four years dropped a total of 20 degrees. What integer represents the average change in the temperature per year? - Suppose 12

Suppose in a physics test involving 30 students, and four scored 75%, eight scored 60%, twelve scored 50%, and six scored 30%. Calculate the mean of the group and the standard deviation.

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