# statistik

can you show me the calculation ;)

The life expectancy of computer terminals is normally distributed with a mean of 4 years and standard deviation for 10 months.

a. What is the probability that a randomly selected terminal will last more than 5 years?

b. What percentage of terminals will last between 2.5 years and 4.5 years?

c. 80 percent of terminals will last at least how many years?

1. 👍
2. 👎
3. 👁
1. Convert all values either into months or years.

Z = (score-mean)/SD

Find table in the back of your statistics text labeled something like "areas under normal distribution" to find the proportions related to the Z scores. To get percentages, multiply by 100.

c. Reverse process to find Z score and calculate.

1. 👍
2. 👎
2. 0.102

1. 👍
2. 👎

## Similar Questions

1. ### Probability & Statistics

The life expectancy (in hours) of a fluorescent tube is normally distributed with a mean 8000 and a standard deviation 1000. Find the probability that a tube lasts for more than 11000 hours.

2. ### P.E

Your friend spends most of his free time eating junk food and playing games on the computer. which way on the health continuum is moving? A. wellness B. long life expectancy C. illness D. obesity i think A

3. ### math

in 1991 the life expectancy of males in a certain country was 73.7 years in 1997 it was 76.9 years let E represent the life expectancy in year T and let T represent the number of years since 1991 the Linear function E (T) that

4. ### statistics

The average life of Canadian women is 73.75 years and the standard deviation of the women's life expectancy in Canada is 6.5 years. Using the Chebyshev's theorem, determine the minimum percentage of women in Canada whose life

1. ### another word problem!

iN 1993, THE LIFE EXPECTANCY of males was 68.6 years. In 2000, it was 71.1 years. Let E represent the life expectancy in year t and t represent the number of years since 1993. The linear function E(t) that fits this data is:

2. ### math (word problem)

In 1994, the life expectancy of males in a certain country was 65.7 years. In 2000, it was 69.0 years. Let E represent the life expectancy in year t and let t represent the number of years since 1994 the linear function E(t) that

3. ### Math

The average life expectancy for American men born in 1900 was 55 years. Life expectancy has increased by about .2 year for each birth year after 1900. If this trend continues, for which birth year will the average life expectancy

4. ### Algebra

In 1992, the life expectancy of males in a certain country was 63.8 years. In 1999, it was 66.0 years. Let E represent the life expectancy in year t and let t represent the number of years since 1992. The lineahntthe nearest ter

1. ### Algebra

In 1991, the life expectancy of males in ceetain country's was 73.3 years. n 1996, it was 75.8 years. Let E represent the life expectancy in year t and let t reprsent the number of years since 1991. The linear fuction E(t) that

2. ### Math

In 1991,the life expectancy of meals in a certain country was 69.8 years. In 1996, it was 72.7 years. Let E represent the life expectancy in year t represent years. E(t)= ____+ _____ Use the function to predict the life expecancy

3. ### Algebra 1

In 1993, the life expectancy of males in a certain country was 67.2 years. In 1999, it was 70.3 years. Let E represent the life expectancy in year t and let t represent the number of years since 1993. The linear function E(t) that

4. ### Algebra

In 1991, the life expectancy of males in a certain country was 67.2 years. In 1995, it was 71.1 years. Let E represent the life expectancy in year t and let t represent the number of years since 1990. The linear function E(t) that