2. The travel time to their workplace of a random sample of workers from thecentral zone of the country is observed in the following frequency table:Minutes15 - 2727393951516363 75Frequency515201510It is assumed that the travel times approximate a normal distribution.Calculate:a) A 90% confidence interval for the population average of travel times.b) A 90% confidence interval for the population standard deviation.

MinutesFrequency15 to 27527 to 391539 to 512051 to 631563 to 7510Sum65

Answered: 2. The travel time to their workplace…

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

For a data set of the pulse rates for a sample of adult females, the lowest pulse rate is 33 beats per minute, the mean of the listed pulse rates is x =74.0 beats per minute, and their standard deviation iss = 13.2 beats per minute. a. What is the difference between the pulse rate of 33 beats per minute and the mean pulse rate of the females? b. How many standard deviations is that [the difference found in part (a)]? c. Convert the pulse rate of 33 beats per minutes to a z score. d. If we consider pulse rates that convert to z scores between -2 and 2 to be neither significantly low nor significantly high, is the pulse rate of 33 beats per minute significant? a. The difference is beats per minute. (Type an integer or a decimal. Do not round.) b. The difference is standard deviations. (Round to two decimal as needed.) c. The z score is z= (Round to two decimal places as needed.) d. The lowest pulse rate is
The distribution of the student heights at a large college is approximately bell shaped. If the mean height is 66 inches,and approximately 95% of the heights fall between 32 and 100 inches, then, the standard deviation of the heightdistribution is approximately equal to
b. In a class of twenty-five 15-year old girls the average height is M = 62.60 inches. The national average for girls at this age is reported as follows: µ = 63.80 inches with a standard deviation, s = 2.66 inches. Compute z score
The distribution of male height (X) in the US is known to be normally distributed with mean of about 70 inches and variance of 25 inches. What is the IQR? (hint: think about what the IQR represents in a boxplot with regard to percentiles). The z tables can be found at the bottom of the written portion of the exam or at the end of Lecture Note 10. a.) 5.0 b.) 9.0 c.) 7.3 d.) 10.0 e.) 6.7
(AKS 24): A technology magazine finds data that suggests the prices of computers with a specific configuration follow an approximately normal distribution with a mean of $895.22 and a standard deviation of $109.30. The magazine wants to describe the percentage of these computers that are priced below $600. WWhat Z-Score should they use? O a) z = 1.3 %3D O b) z = -1.3 c) z = -2.7 %3D d) z = 2.7 Question 2 (1 point) (AKS 24): A set of laptop prices are normally distributed with a mean of $750 and a
At a tennis tournament a statistician keeps track of every serve. The statistician finds that the mean serve speed of a particular player was 110 miles per hour (mph) and the standard deviation of the serve speeds was 5 mph. Assume that the distribution of the serve speeds was bell shaped. Using the Empirical Rule, find the following. a) percent of serves expected to be above 120mph. b) proportion of serves expected to be between 105mph and 125mph. c) proportion of serves expected to be below 105mph. d) percent of serves expected to be within 3 standard deviations of the mean.
The owner of a fish market has an assistant who has determined that the weights of catfish are normally distributed, with a mean of 3.2 pounds and a standard deviation of 0.8 pound. If a sample of 25 fish yields a mean of 3.1 pounds, what is the Z-score for this observation? Question 3 options: 1) 2.500 2) 0.625 3) -0.625 4) 1.250
The results from a statistics class’ first test are as follows: The average grade obtained on the test by its 45 students is an 85, with a standard deviation of 15 points. Answer the following based on this information: a. Approximately how many people received a failing grade (less than 65) b. What percentage of people received a grade between a 70 and a 91? c. What percentage of individuals received a score whose z-score was -.70 or less? d. What grade is required in order to be in the top 15 percent? The top 10 percent? e. What percentage of people received a grade between 85 and 95? f. What percentage of people received a grade of 94 or less? g. What grade is required to be in the bottom 20%? h. What z-score is required to be in the top 40%? i. What percentage of individuals have a z-score between -1 and 1.40? j. What percentage of individuals have a z-score between 1.05 and 1.40?

Recommended textbooks for you

A First Course in Probability (10th Edition)

Probability

ISBN:

9780134753119

Author:

Sheldon Ross

Publisher:

PEARSON

A First Course in Probability

Probability

ISBN:

9780321794772

Author:

Sheldon Ross

Publisher:

PEARSON

A First Course in Probability (10th Edition)

Probability

ISBN:

9780134753119

Author:

Sheldon Ross

Publisher:

PEARSON

A First Course in Probability

Probability

ISBN:

9780321794772

Author:

Sheldon Ross

Publisher:

PEARSON

SEE MORE TEXTBOOKS