# statistics

posted by .

A normal distribution has a mean of µ = 100 with standard deviation = 20. If one score is randomly selected from this distribution, what is the probability that the score will have a value between X = 80 and X = 100?

• statistics -

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportion between the two Z scores.

• statistics -

so confused

## Similar Questions

1. ### Statistics

The Wechsler Adult Intelligence Scale (WAIS) is a common "IQ test" for adults. The distribution of WAIS scores for persons over 16 yrs of age is approximately Normal with mean (100) and Standard Deviation 15, (a) Whatis the probability …
2. ### Math

A normal distribution has a mean of 20 and a standard deviation of 3.What is the probability that a randomly selected x-value from the distribution is: A)at least 14?
3. ### AP Statistics - sampling distribution help

The composite scores of students on the ACT college entrance examination in a recent year had a Normal distribution with mean µ = 20.4 and standard deviation = 5.8. 1) What is the probability that a randomly chosen student scored …
4. ### AP Statistics - Sampling Distribution Help

The composite scores of students on the ACT college entrance examination in a recent year had a Normal distribution with mean µ = 20.4 and standard deviation = 5.8. 1) What is the probability that a randomly chosen student scored …
5. ### statistics

A normal distribution has a mean of 100 and standard deviation of 20. What is the probability of randomly selecting a score less than 130 from this distribution?
6. ### Statistics

A normal distribution has a mean of ƒÝ = 100 with ƒã = 20. If one score is randomly selected from this distribution, what is the probability that the score will have a value between X = 90 and X = 110?
7. ### statistics

True or False If one score is randomly selected from a normal distribution with  = 100 and  = 20, the probability of obtaining a score between X = 80 and X = 120 is 0.3413.
8. ### Statistics

The distribution of IQ scores is a nonstandard normal distribution with a mean of 100 and a standard deviation of 15. What are the value of the mean and standard deviation after all IQ score have been standardized by converting them …
9. ### distribution

In a school, the IQ scores of the students have a normal distribution with a mean value of 100, and a standard deviation of 10. What is the probability that the IQ score of a randomly selected student is at least 120?
10. ### statistics

a normal distribution has a mean of 20 and a standard deviation of 10. Two scores are sampled randomly from the distribution and the second score is subtracted from the first. What is the probability that the difference score will …

More Similar Questions