# 0.1 Review exercises (ch 3-13)  (Page 5/12)

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52. Which of the following distributions is described by the following example?
Many people can run a short distance of under two miles, but as the distance increases, fewer people can run that far.

1. binomial
2. uniform
3. exponential
4. normal

53. The length of time to brush one’s teeth is generally thought to be exponentially distributed with a mean of $\frac{3}{4}$ minutes. Find the probability that a randomly selected person brushes his or her teeth less than $\frac{3}{4}$ minutes.

1. 0.5
2. $\frac{3}{4}$
3. 0.43
4. 0.63

54. Which distribution accurately describes the following situation?
The chance that a teenage boy regularly gives his mother a kiss goodnight is about 20%. Fourteen teenage boys are randomly surveyed. Let X = the number of teenage boys that regularly give their mother a kiss goodnight.

1. B (14,0.20)
2. P (2.8)
3. N (2.8,2.24)
4. Exp $\left(\frac{1}{0.20}\right)$

55. A 2008 report on technology use states that approximately 20% of U.S. households have never sent an e-mail. Suppose that we select a random sample of fourteen U.S. households. Let X = the number of households in a 2008 sample of 14 households that have never sent an email

1. B (14,0.20)
2. P (2.8)
3. N (2.8,2.24)
4. Exp $\left(\frac{1}{0.20}\right)$

## Chapter 8

Use the following information to answer the next three exercises: Suppose that a sample of 15 randomly chosen people were put on a special weight loss diet. The amount of weight lost, in pounds, follows an unknown distribution with mean equal to 12 pounds and standard deviation equal to three pounds. Assume that the distribution for the weight loss is normal.

56. To find the probability that the mean amount of weight lost by 15 people is no more than 14 pounds, the random variable should be:

1. number of people who lost weight on the special weight loss diet.
2. the number of people who were on the diet.
3. the mean amount of weight lost by 15 people on the special weight loss diet.
4. the total amount of weight lost by 15 people on the special weight loss diet.

57. Find the probability asked for in Question 56 .

58. Find the 90 th percentile for the mean amount of weight lost by 15 people.

Using the following information to answer the next three exercises: The time of occurrence of the first accident during rush-hour traffic at a major intersection is uniformly distributed between the three hour interval 4 p.m. to 7 p.m. Let X = the amount of time (hours) it takes for the first accident to occur.

59. What is the probability that the time of occurrence is within the first half-hour or the last hour of the period from 4 to 7 p.m.?

1. cannot be determined from the information given
2. $\frac{1}{6}$
3. $\frac{1}{2}$
4. $\frac{1}{3}$

60. The 20 th percentile occurs after how many hours?

1. 0.20
2. 0.60
3. 0.50
4. 1

61. Assume Ramon has kept track of the times for the first accidents to occur for 40 different days. Let C = the total cumulative time. Then C follows which distribution?

1. U (0,3)
2. Exp (13)
3. N (60, 5.477)
4. N (1.5, 0.01875)

62. Using the information in Question 61 , find the probability that the total time for all first accidents to occur is more than 43 hours.

Use the following information to answer the next two exercises: The length of time a parent must wait for his children to clean their rooms is uniformly distributed in the time interval from one to 15 days.

change of origin and scale
3. If the grades of 40000 students in a course at the Hashemite University are distributed according to N(60,400) Then the number of students with grades less than 75 =*
If a constant value is added to every observation of data, then arithmetic mean is obtained by
sum of AM+Constnt
Fazal
data can be defined as numbers in context. suppose you are given the following set of numbers 18,22,22,20,19,21
what are data
what is mode?
what is statistics
Natasha
statistics is a combination of collect data summraize data analyiz data and interprete data
Ali
what is mode
Natasha
what is statistics
It is the science of analysing numerical data in large quantities, especially for the purpose of inferring proportions in a whole from those in a representative sample.
Bernice
history of statistics
statistics was first used by?
Terseer
if a population has a prevalence of Hypertension 5%, what is the probability of 4 people having hypertension from 8 randomly selected individuals?
Carpet land sales persons average 8000 per weekend sales Steve qantas the firm's vice president proposes a compensation plan with new selling incentives Steve hopes that the results of a trial selling period will enable him to conclude that the compensation plan increases the average sales per sales
Supposed we have Standard deviation 1.56, mean 6.36, sample size 25 and Z-score 1.96 at 95% confidence level, what is the confidence interval?
if Y=a+bX and X=c+dY the show that |r|= √hd where r is regression coefficient
this is a linear function. I presume this will be solved simultaneously?
no
Naheed
how can I get esyer statistic?
yes
pakistan
msc completed
i am bba students at nfc
Hamdan
stat. is the subject in bba .... exam is online . .. which fee u charge to slove my exam ?
Hamdan
which uni u completed msc?
Hamdan
no charges. i am just helping you. not for fees
really
Hamdan
yeap
i am so glad this type of people lived in pakistan💔
Hamdan
but unfortunately bba students just live for money🤣
Hamdan
no purpose of life without money🤠
Hamdan
money is not everything
Hamdan
ok ye tu easy topic h bhot
main tume is se related ques aur theory bejti ho
in an examination 60% passed in physics 52% passed in statistics. while 32% failed in both the subject's using relations between class frequencies in attributes find the percentage of student passed in both the subject's
Satish
Hamdan
apply
Hamdan
Find the multiple regression line Y on X1 and X2 from the following data, also interpret the estimated parameters and calculate standard error of estimate. Y 90 72 54 42 30 12 10 X1
how old are the children needed
?
Afolabi