An electric company has been selling a bulb, which was advertised as having an average life of 1,500 hours. Assume that the lifetime of these bulbs is normally distributed with a standard deviation of 800 hours. A random sample of 16 bulbs from this manufacturing process was tested and their lifetimes were recorded. a)What is the probability that the sample mean is between 1, 250 and 1,750 hours? Step by step solution

An electric company has been selling a bulb, which was advertised as having an average life of 1,500 hours. Assume that the lifetime of these bulbs is normally distributed with a standard deviation of 800 hours. A random sample of 16 bulbs from this manufacturing process was tested and their lifetimes were recorded. a)What is the probability that the sample mean is between 1, 250 and 1,750 hours? Step by step solution

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

Suppose that unknown to a geneticist, there are 6 out of 12 genes that play a significant role in developing skin cancer. If the geneticist randomly samples 5 of these 12 genes and studies them, the probability that he will have sampled more than 4 skin cancer related genes is Note: Provide your answer in three decimal points e.g. 0.001
Consider a normally distributed random variable X with a mean of 85 and standard deviation of 10. Find ? The probability that a patient recovers from a rare blood disease is 0.4. If 15 people are known to have contracted this disease, what is the probability that 3 to 8 will survive?
A random sample of 40 computer chips is drawn from population and the weight of each recorded. A previous study showed that the population mean weight was 0.8 ounces with a standard deviation of 0.1 ounces. What is the probability that the sample has a mean weight between 0.75 and 0.90 ounces?
A population has an average of 125 and a standard deviation of 15. Calculate the probability that in a sample of size 75, the sample mean is greater than 130.
Seventy million pounds of trout are grown in the U.S. every year. Farm-raised trout contain an average (mean) of 32 grams of fat per pound, with a standard deviation of 8 grams of fat per pound. A random sample of 40 farm-raised trout is selected. The mean fat content for the sample is 30.2 grams per pound. Find the probability of observing a sample mean of 30.2 grams of fat per pound or less in a random sample of 40 farm-raised trout. Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places. Check esc 23 2$ 5 2 e r t y tab
The level of nitrogen oxides (NOX) and nonmethane organic gas (NMOG) in the exhaust over the useful life (150,000150,000 miles of driving) of cars of a particular model varies Normally with mean 8080 mg/mi and standard deviation 66 mg/mi. A company has 1616 cars of this model in its fleet. Using Table A, find the level ?L such that the probability that the average NOX + NMOG level ?¯x¯ for the fleet greater than ?L is only 0.030.03 ? (Enter your answer rounded to three decimal places. If you are using CrunchIt, adjust the default precision under Preferences as necessary. See the instructional video on how to adjust precision settings.)
According to one study, the amount of time a customer spends shopping in a grocery store is normally distributed with a mean of 45 minutes and a standard deviation of 12 minutes. Choose one: The amount of time a customer spends shopping is a discrete random variable. The amount of time a customer spends shopping is a continuous random variable.
Seventy million pounds of trout are grown in the U.S. every year. Farm-raised trout contain an average (mean) of 32 grams of fat per pound, with a standard deviation of 8 grams of fat per pound. A random sample of 34 farm-raised trout is selected. The mean fat content for the sample is 31.8 grams per pound. Find the probability of observing a sample mean of 31.8 grams of fat per pound or less in a random sample of 34 farm-raised trout.Carry your intermediate computations to at least four decimal places. Round your answer to at least three decimal places.
A production line in a factory, assembles laptops. A random sample of assembly time of 36 laptops has been drawn from this factory. Suppose, the population distribution has a mean assembly time of 25 minutes and standard deviation 6 minutes. What is the probability that a sample mean is 26 minutes? Select one: a. 0.0 b. =P(Z>1) c. =P(Z=0) d. =P(Z<1) e. None of the others
The photoresist thickness of wafers in semiconductor manufacturing has a mean of 10.6 micrometers and a standard deviation of 1.3 micrometers. An engineer takes a sample of 50 wafers once a week and calculates the mean thickness of these wafers. If the mean of this sample is either less than 10.41 micrometers or greater than 10.79 micrometers, the engineer will conclude that the machine needs an adjustment. The probability that, based on a sample of 50 wafers, the engineer will conclude that the machine needs an adjustment is: O 0.6970 O 0.1091 O 0.3030 O 0.2522 O 0.1506
Suppose our random variable is the braking distance of a certain car in feet on a dry surface when going 55mph. The mean braking distance is 148 feet and the standard deviation is 2.64 feet. We randomly sample 33 braking distances from this population, what is the probability that the mean braking distance for the sample is between 147.6 feet and 150 feet?