Question

In: Statistics and Probability

The times that college students spend studying per week have a distribution skewed to the right...

The times that college students spend studying per week have a distribution skewed to the right with a mean of 8.3 hours and a standard deviation 2.6 of hours. Find the probability that the mean time spent studying per week for a random sample of 55 college students would be a. between 7.6 and 8.4 hours. Round your answer to two decimal places. b. less than 8.1 hours. Round your answer to two decimal places.

THE ANSWERS ARE NOT .49 AND .19

Solutions

Expert Solution

Solution :

Given that ,

mean = = 8.3

standard deviation = = 2.6

n = 55

= = 8.3

= / n = 2.6 / 55 = 0.3506

a)

P(7.6 < < 8.4) = P((7.6 - 8.3) / 0.3506<( - ) / < (8.4 - 8.3) / 0.3506))

= P(-2.00 < Z < 0.29)

= P(Z < 0.29) - P(Z < -2.00) Using standard normal table,  

= 0.6141 - 0.0228

= 0.5913

Probability = 0.59

b)

P( > 8.1) = 1 - P( < 8.1)

= 1 - P(( - ) / < (8.1 - 8.3) / 0.3506)

= 1 - P(z < -0.57)

= 1 - 0.2843 Using standard normal table.

= 0.7157

Probability = 0.72


Related Solutions

The times that college students spend studying per week have a distribution skewed to the right...
The times that college students spend studying per week have a distribution skewed to the right with a mean of 7.6 hours and a standard deviation of 2.6 hours. Find the probability that the mean time spent studying per week for a random sample of 45 college students would be a. between 7.0 and 7.9 hours. Round your answer to two decimal places. P=____ b. less than 7.3 hours. Round your answer to two decimal places. P=____
The times that college students spend studying per week have a distribution that is skewed to...
The times that college students spend studying per week have a distribution that is skewed to the right with a mean of 7.0 hours and a standard deviation of 2.4 hours. Find the probability that the mean time spent studying per week for a random sample of 45 students would be a. between 7.4 and 8.2 hours. b. less than 7.4 hours . Note 1: Round your z values to 2 decimal places before looking them up in the table...
Students studying at GWU spend an average of $172.50 per week on basic needs other than...
Students studying at GWU spend an average of $172.50 per week on basic needs other than housing. Use this figure as the population mean and assume that population standard deviation is $75.00. What is the probability that the mean expenditure for a sample of 35 students is within $20 of the population mean? What assumption do you need to make for this calculation? What is the probability that the mean expenditure for a sample of 50 students is within $20...
From past studies the average time college freshmen spend studying is 22 hours per week. The...
From past studies the average time college freshmen spend studying is 22 hours per week. The standard deviation is 4 hours. This year, 60 students were surveyed, and the average time that they spent studying was 20.8 hours. Test the claim that the time students spend studying has not changed. Use a=1%
Do male college students spend more time studying than female college students? This was one of...
Do male college students spend more time studying than female college students? This was one of the questions investigated by the authors of an article. Each student in a random sample of 46 male students at a university in England and each student in a random sample of 38 female students from the same university kept a diary of how he or she spent time over a 3-week period. For the sample of males, the mean time spent studying per...
from past studies the average time college freshmen spend studying n 22 hours per week. The...
from past studies the average time college freshmen spend studying n 22 hours per week. The standard deviation is 4 hours. This year, 60 students were surveyed, and the average time that they spent studying was 20.8 hours. Test the claim that the time students spend studying has not changed. Use a=1%
A national study found that college students spend an average of 150 ( = 150) studying...
A national study found that college students spend an average of 150 ( = 150) studying during their first semester. A group of 41 AAMU students participated in The AAMU summer bridge students studied an average of 146 hours (M = 146) during their first semester. With a sum of squared deviations of 2,367 (SS – 2,367) and a significance level of α = .01, did the summer bridge students differ in the number of hours studied compared to college...
If a population of college student ages is skewed right, then this indicates?
If a population of college student ages is skewed right, then this indicates?
A nationwide survey of college students was conducted and found that students spend two hours per...
A nationwide survey of college students was conducted and found that students spend two hours per class hour studying. A professor at your university wants to determine whether the time students spend at your university is significantly different from the two hours. A random sample of 36 statistics students is carried out and the findings indicate an average of 1.75 hours. Assume a populatoin standard deviation of 0.5 hours. Using a level of significance of 0.05: 1. Construct a 95%...
If a distribution is skewed right, then the median for this population is smaller than the...
If a distribution is skewed right, then the median for this population is smaller than the median for the sampling distribution of sample means with sample size 80. True or False
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT