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...

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b) Find the mean and the standard deviation of the times in the following table. Because the table contains all the winning times for this race (up to year 2012), the data set is a population. Olympic Women's 400-Meter Dash Results, in Seconds, 1969-2012 52.0 51.08 49.29 48.88 48.83 48.65 48.83 48.25 49.11 49.41 49.62 49.55
Fifteen randomly selected college students were asked to state the number of hours they slept the night before. The resulting data are: 6 16 7 8 7 796 3 11 9 15 4 7 9 a) Find the mean. b) Find the median. c) Find the standard deviation. d) According to Chebysev's Theorem, at least 75% of the times will fall between what two amounts? Is the theorem accurate for this set of data? Why of Why not? e) Are any of the reported hours "unusually" high? Are any of the reported hours unusually low?
b.
A team of ten (10) construction workers who are working on a project are classified according to the skill levels, Classes A to D. The table below shows the number of workers in each of the four (4) classes and their respective hourly pay-rate. Pay-rate (Rands/hour) Number of workers Class A 80 Class B 60 Class C 55 Class D 50 4. Calculate the mean hourly pay-rate for the 10 workers. A. R24.50/hour B. R57/hour C. R57.50/hour D. R61.75/hour
(b) Calculate the mean, median mode and standard deviation for the following data: 4600- 4800 75 4800- 5000 5000- 5200 5200- 5400 50 4000- 4400- Class size 4200 22 4200- 4400 38 4600 Freque 65 80 70
The length of preg…
9. Determines the average, median and standard deviation of each of the distributions to a variable (age, girl reaction time and boys reaction time).What interpretations can you make of it? B.) For each of the three two-variable distributions, make a graphical representation using a technological tool and calculate the values that can be used to interpret them. C.) Interpret graphic representations and draw conclusions.
The mean age of all 663 used cars for sale in a newspaper one Saturday last month was 7.5 years, with a standard deviation of7.1 years. The distribution ads, a reporter randomly selects 50 of these used cars and plans to visit each owner to inspect the cars. He finds that the mean age of the 50 cars he sam Complete parts a through c. a From the problem statement, which of the values 75,7.1, 7.9, and 5.6 are parameters and which are statistics? The value 7.5 is a The value 7.1 is a The value 7.9 is a The value 5.6 is a
3. The average height of a male student in the EDA class of Engr. Ventura in PLM has historically been 1.625 meters with a standard deviation of 0.07 meter. Is there a reason to believe that there has been a change in the average height of male EDA students under Engr. Ventura if a random sample of 50 males in the present EDA class has an average height of 1.652 meters? Assume the standard deviation remains the same.
1.Determines in a table, the average, median and standard deviation of each of the distributions to a variable (age, girl reaction time and boys reaction time).What interpretations can you make of it? A.) For each of the three two-variable distributions, make a graphical representation using a technological tool and calculate the values that can be used to interpret them. B.) Interpret graphic representations and draw conclusions.
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?

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