11. In a certain test, 35 percent of the tested population scored higher than 6, 25 percent between 4 and 6, and 40 percent below 4. Assuming that the scores follow a normal distribution, calculate the average grade and the standard deviation. a) What percentage of the population has a grade that differs from the mean by less than 2 units

11. In a certain test, 35 percent of the tested population scored higher than 6, 25 percent between 4 and 6, and 40 percent below 4. Assuming that the scores follow a normal distribution, calculate the average grade and the standard deviation. a) What percentage of the population has a grade that differs from the mean by less than 2 units

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

See similar textbooks

Similar questions

Suppose the exam average in a class is 55% with a standard deviation of 4. What proportion of students scored above 57%? Round to two places.
The weights of tablets are normally distributed with mean 254 mg and standard deviation 4 mg. If exactly 1% of tablets are ‘overweight’, then what weight makes the tablet ‘overweight’?
1. What does the standard deviation measure?
The mean wage per hour for all 4000 employees working at a large company is RM 10.50 with a standard deviation of RM 5.30. Let x be the mean wage per hour for a random sample of certain employees selected from this company.
Find out mean deviation from mean by applying direct method from the following distribution: Values: 48, 50, 46, 44, 40, 42, 35, 30, 20, 15.
7. Calculate -scores for the following raw scores taken from a population with a mean of 100 and standard deviation of 16: 112, 109, 56, 88, 135, 99 Answer: 2 = 0.75, 0.56, -2.75, -0.75, 2.19, -0.06 show work for these please
After the physical training required during World War II the distribution of a mile run times for male students at the University of Illinois was approximately normal with a mean of 7.11 minutes in a standard deviation of 0.74 minutes what proportion of these students can run a mile in 5 minutes or less Using the same data what percent of students would take between 6 and 8 minutes to run a mile
Suppose that blood chlorine concentration (mmol/L) has a normal distribution with mean=98 and standard deviation=7. For a sample of n=40, what is the corresponding mean and standard deviation of the sampling distribution?
The number of hours per week that the television is turned on is determined for each family in a sample. The mean of the data is 31 hours and the median is 27.2hours. Twenty-four of the families in the sample turned on the television for 16 hours or less for the week. The 8th percentile of the data is 16 hours. Based on the given information, determine if the following statement is true or false. The first quartile is less than 16 hours.
On an intelligence test, the mean number of raw items correct is 236 and the standard deviation is 39. What are the raw (actual) scores on the test for people with IQs of (a) 119, (b) 81, and (c)100? To do this problem, first figure the Z score for the particular IQ score; then use that Z score to find the raw score. Note that IQ scores have a mean of 100 and a standard deviation of 15. (a) What is the raw (actual) score on the test for people with an IQ of 119?