# Math-statistics

Assume that a set of test scores is normally distributed with a mean of 100 and a standard deviation of 20. Use the 68-95-99.7 rule to find the following quantiles: a.percentage of scores less than 100 b. relative frequency of scores less than 120 c. percentage of scores less than 140 d. percentage of scores less than 80. e. relative frequency of scores less than 60 f. percentage of scores greater than 120

1. 👍
2. 👎
3. 👁
1. 40 60 80 100 120 140 160

This represents +/- 3 standard deviations.

68% falls within 80 and 120
95% falls within 60 and 140
99.7% falls within 40 and 160

Using this information and a diagram, I think you will be able to answer wthe questions.

1. 👍
2. 👎
2. a.percentage of scores less than 100

1. 👍
2. 👎

## Similar Questions

1. ### Statistics

IQ test scores are normally distributed with a mean of 100 and a standard deviation of 15. Find the x- score that corresponds to a z-score of 2.33.

2. ### Math

Find the mean of the data set. If necessary, round to the nearest tenth. 15.8, 14.9, 17.6, 13.4. A) 15.7 ***** B) 16.2 C) 16.7 D) 19.6 Erin wrote the following set of numbers. 37, 22, 37, 19, 34, 22, 37, 22, 32, 26, 30, 22 What is

3. ### Statistics

The National Assessment of Educational Progress tested a simple random sample of 1000 thirteen year old students in both 2004 and 2008 and recorded each student's score. The average and standard deviation in 2004 were 257 and 39,

4. ### statistics

IQ scores are normally distributed with a mean u = 100 and a standard deviation o =15. Based on distribution, determine % of IQ scores between 100 and 120 =

1. ### Math

Suppose scores on an IQ test are normally distributed. If the test has a mean of 100 and a standard deviation of 10, what is the probability that a person who takes the test will score between 90 and 110?

2. ### statistics

find the indicated IQ score. The graph depicts IQ scores of adults, and those scores are normally distributed with a mean of 100 and and a standard deviation of 15 The shaded area under the curve is 0.10 119.2 100.5 108.1 80.8

3. ### Statistics

The scores on a math test are normally distributed. if the mean is 72 and the standard deviation is six, what is the range of 98% of the scores?

4. ### stats.

The GMAT test is required for admission to most graduate programs in business. In a recent year, the GMAT test scores were normally distributed with a mean of 550 and standard deviation of 100. A. Find the first quartile for the

1. ### Math

The mean of a set of four test scores is 85. If three of the test scores are 81,83, and 85, what is the fourth test score? A. 89 B. 87 C. 91 D. 85 Is the answer A? Thank you

2. ### statics

Using the 68-95-99.7rule. Assume that a set of test scores is normally distributed with a mean of 80 and a standard deviation of 25. Use the 68-95-99.7 rule to find the following quantities. percentage of scores greater than 105

3. ### math new question

15. Which of the following would best display information in a frequency table that has been divided into categories? bar graph**** pictograph circle graph histogram 14. The mean of a set of four test scores is 85. If three of the

4. ### statistics!

1) Entry to a certain University is determined by a national test. The scores on this test are normally distributed with a mean of 500 and a standard deviation of 100. Tom wants to be admitted to this university and he knows that