WorksheetsEstimation
Total questions: 10
Worksheet time: 17mins
A sample size of n = 64 is drawn from a population whose standard deviation is σ = 5.6.
Find the margin of error for a 99% confidence interval for µ.
1.799
1.798
1.803
A large sample has mean of 7.1 and Standard Error of 2.3.
Construct a 90% Confidence Interval for the population mean µ (to two decimal places).
(3.32, 10.88)
(3.8, 7.1)
(3.3, 10.9)
(3.3165, 10.8835)
An IQ test was given to a simple random sample of 75 students at a certain college. The sample mean score was 105.2. Scores on this test are known to have a standard deviation of 10. It is desired to construct a 90% confidence interval for the mean IQ scores of the students at the college.
Find the Margin of Error to two decimal places.
1.90
1.89
1.899
1.99
The lifetime of a certain type of batter is known to be normally distributed with a standard deviation of 20 hours. A sample of 50 batteries had a mean lifetime of 120.1 hours. It is desired to construct a 99% confidence interval for the mean lifetime of this type of battery.
What is the Confidence Interval to one decimal place?
(114.5, 125.6)
(112.8, 127.4)
(112.82, 127.38)
(114.56, 125.64)
If the 95% Confidence Interval for a population mean is (114.56, 125.54), then is it likely that the true population mean µ is greater than 130?
Yes
No
Not enough information
I have no idea what you're asking of me
Given the Critical Value of Z = 2.11, find the Confidence Level.
96.52%
0.9652
.9826
98.26%
Find the Critical Value for an 86% Confidence Level.
-1.48
1.48
1.282
-1.47
True or False:
The more confident you want to be, the smaller your confidence interval will be.
True
False
A quality control specialist at a glass factory must estimate the mean clarity rating for a new batch of glass using a sample of 18 glass sheets from the batch. Past investigations show that clarity ratings are normally distributed. The specialist decides to use a t-distribution rather than a z-distribution because ...
The t distribution is more accurate than a z distribution.
Clarity ratings for the entire bacth are normally distributed.
The t-distribution will create a narrower interval than z.
The standard deviation for the population is unknown.
In a crash test of 15 troopers, collision repair costs are found to have a distribution that is approximately normal, with a mean of $1800 and a standard deviation of $950. Construct a 99% confidence interval for the repair cost for the population.
(1070, 2530)
(1273, 2326)
(1799, 1801)
(1776, 1823)
