(a) Based on a recent study, the monthly utility bills for three-room flats in Singapore can be assumed to be normally distributed with mean $135 and standard deviation $42. If a household living in a three-room flat is randomly selected, i. What is the probability that its utility bill is more than $155 ii. What is the probability that its utility bill is between $129 and $165? ii. If 20% of the utility bills for households living in three-room flats are above a certain value V, find the value of V.

(a) Based on a recent study, the monthly utility bills for three-room flats in Singapore can be assumed to be normally distributed with mean $135 and standard deviation $42. If a household living in a three-room flat is randomly selected, i. What is the probability that its utility bill is more than $155 ii. What is the probability that its utility bill is between $129 and $165? ii. If 20% of the utility bills for households living in three-room flats are above a certain value V, find the value of V.

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

A. If 75% of high school students are able to pass a stats test, find the mean, variance, and standard deviation for the number of students who pass the test in a sample of 150 students. B. What is the probability that just you will not pass this test, if all 22 students take the test?
LightCastle Partners, a Bangladeshi business management consultant, employs a large number of data analysts to analyze the data in a survey project. The time it takes for new data analysts to learn the analysis procedure is known to have a normal distribution with a mean of 99 minutes and a standard deviation of 14 minutes. a. What is the probability that the new data analysts will take more than 103 minutes to learn the analysis procedure? b. What is the probability that the new data analysts will take between 65 to 134 minutes to learn the analysis procedure? c. To maintain employee standars, LightCastle does not hire any analyst who fails to learn the process within a specified time. Therefore, what should be the specified time limit if they wish to retain at most 91.24% of new analysts?
PLS. Solve Quickly Applications Problems According to a Sallie Mae survey and credit bureau data, in 2008, college students carried an average of $3173 debt on their credit cards (USA TODAY, April 13, 2009). Suppose that cur- rent credit card debts for all college students have a normal distribution with a mean of $3173 and a standard deviation of $800. Find the probability that credit card debt for a randomly se- lected college student is between $2109 and $3605.
According to College Board, the average out-of-state tuition for a four-year public college was $8,893 for the 2013-2014 academic year. There are a total of 629 four-year public institutions in the U.S. Assume that the standard deviation for the tuition for these colleges is $950. A random sample of 60 four-year public colleges was selected. What is the probability that the average tuition from this sample is less than $9,000?
1. Lori just bought a set of 4 tires for her car. The life of a tire is normally distributed with a mean of 45000 miles and a standard deviation of 2000 miles. Find the probability that all 4 tires will last for at least 46000 miles. Assume independence of tires between one another.
In a recent study reported Oct. 29, 2012 on the Flurry Blog, the mean age of tablet users is 34 years. Suppose the standard deviation is 15 years. Take a sample of size n = 100. a. What are the mean and standard deviation for the sample mean ages of tablet users? b. What does the distribution look like? c. Find the probability that the sample mean age is more than 30 years (the reported mean age of tablet users in this particular study). d. Find the 95th percentile for the sample mean age (to one decimal place).
Suppose that the distribution of the grades of students in MAPEH performance 1 is roughly normally distributed with a mean of 85 and a standard deviation of 5 a. Between what values do we expect the grades of the middle 68% of the MAPEH students in performance 1 lie? b. Suppose you randomly select 16 MAPEH students, find the probability that the average grades of these students is at least 86. c. A MAPEH student whose grades lies in the upper 1% of the distribution (inclusive of the 1% cutoff) is considered extremely performing in Performance 1. Can you say that Jazzer, a randomly selected student who obtained a grade of 95, is one of those who performed extremely in Performance 1?
Suppose a population distribution has a mean = 150 and a standard deviation s = 30, and you draw a simple random sample of N = 100 cases. What is the probability that the mean is between 147 and 153?
The waiting time before service in a bank is exponentially distributed with a mean waiting time of 5 minutes.a. What is the median waiting time.b. You enter the bank and find that your friend has been waiting in the queue for service for past 2 minutes. Upon your arrival what is the probability that your friend will wait for another 4 minutes?c. What is the mean and variance of the waiting time in the bank?
A. The salaries of pharmacy techs are normally distributed with a mean of $33,000 and a standard deviation of $4,000. If a pharmacy tech is selected at random, what is the probability they make more than $38,000? The answer should be typed as a decimal with 4 decimal places. B. The salaries of pharmacy techs are normally distributed with a mean of $33,000 and a standard deviation of $4,000. What is the minimum salary to be considered the top 6%? Round final answer to the nearest whole number. C. The average number of shoppers at a particular grocery store in one day is 505, and the standard deviation is 115. The number of shoppers is normally distributed. For a random day, what is the probability that there are between 250 and 450 shoppers at the grocery store? The answer should be typed as a decimal with 4 decimal places.
e) Suppose that weekly household expenditures on petrol are normally distributed, with a mean of $120 and a standard deviation of $50. i. A family is randomly selected. Find the probability that this family spends more than $245 per week on petrol? A 2.5 B 0.0062 C 0.9938 D 0.0202 ii. The government wants to promote public transport and will award a prize to the families who spend the lowest amount on petrol. If the government only wants to give a prize to 10% of households, what is the most that a family is allowed to spend on petrol each week to obtain the prize? A $56 B $184 C $3.50 D $217.60 In a sample of 25 families, what is the probability that the average weekly expenditure on petrol will be less than $105? ii. A 0.0668 B 0.9332 C 0.3821 D 0.6179
4. A manufacturer produces 25-pound lifting weights. The lowest actual weight is 24 pounds, and the highest is 26 pounds. Each weight is equally likely so the distribution of weights is uniform. A sample of 100 weights is taken. a. What is the distribution for the weights of one 25-pound lifting weight? What is the mean and standard deviation? b. What is the distribution for the mean weight of 100 25-pound lifting weights? c. Find the probability that the mean actual weight for the 100 weights is less than 24.9. 1 I