Confidence Intervals and Hypothesis TestingName:
Math 256, Nelson

1. A soft-drink machine is regulated so that the amount of drink dispensed is approximately normally distributed with a standard deviation equal to 1.5 deciliters. Find a 95% confidence interval for the mean of all drinks dispensed by this machine if a random sample of 36 drinks had an average content of 2.25 dl.

2. The heights of a random sample of 50 college students showed a mean of 174.5 centimeters. Assume the standard deviation is 6.9 cm. What can we assert with 98% confidence about the possible size of our error if we estimate the mean height of all college students to be 174.5?

3. How large a sample is needed in #1 above is we wish to be 95% confident that our sample mean will be within 0.3 dl of the true mean?

4. A random sample of 1000 recorded deaths in the United States during the past year showed an average life span of 71.8 years. Assume a standard deviation of 8.9 years. Find a 95% confidence interval for the actual average life span.

5. On a certain national school test [pic]and [pic]. A principal claims that her students are above average. She takes a random sample of 75 and finds a mean of 525. Is her claim justified?

6. A random sample of 100 recorded deaths in the United States during the past year showed an average life span of 71.8 years. Assuming a standard deviation of 8.9 years, can we conclude that the actual life span is not 75 years? [pic]

7. A manufacturer of sports equipment has developed a new synthetic fishing line that he claims has a mean breaking strength of 8 kilograms. Test the hypothesis that the mean is 8 kg against the alternative that it is less than 8 kg, if a random sample of 50 lines is tested and found to have a mean breaking strength of 7.8 kg. The standard deviation is 0.8 kg. Use a 0.01 level of significance.

...indicated to what kind of test was going to be used and since I claimed that the rural area were going to have a lower average number of beds it states that the shaded area on the critical value test will be less than zero.
Table 1. Descriptive statistics for the given null and alternative hypothesis that includes the sample, mean, median, standard deviation, maximum values, and minimum values.
Sample Size
Mean
Median
Standard Deviation
Maximum Value
Minimum Value
Rural Area...

...Normal(88.532,5.07943)
Normal(97.1033,5.04488)
Normal(107.15,5.15367)
Summary Statistics
Mean
88.532
Std Dev
5.0794269
Std Err Mean
0.2271589
Upper 95% Mean
88.978306
Lower 95% Mean
88.085694
N
500
Sum
44266
Summary Statistics
Mean
97.103333
Std Dev
5.0448811
Std Err Mean
0.2912663
Upper 95% Mean
97.676525
Lower 95% Mean
96.530142
N
300
Sum
29131
Summary Statistics
Mean...

...BUS 105e:
Statistics
By Dr Tony Halim
GBA: 27 February 2013
Done by:
Koh En Song Andrew (Q1211397)
Melissa Teo Kah Leng (E1011088)
Woon Wei Jie Jared
T 04
1.
Over the span of 100 days, the total revenue for Unicafe North and Unicafe West is $21876.60 and $22042.00 respectively. The average revenue for Unicafe North is $218.77. The average revenue for Unicafe West is $220.42. The highest revenue occurred on the 88th day for both outlets. The lowest revenue...

...MAT 300: STATISTICS
M&M PROJECT PAPER
ALEXANDREA WINT
PROFESSOR AZAD, VARGHA
June 3, 2012
Purpose of Report
The purpose of this project is to find the information for a quality control manager of Masterfoods plant. The manager wants to know about the proportion of candies and if they are the same or different. If there is any difference that exists then the manager wants to know why there is a difference in such cases. A study was conducted and results were...

...
November 19, 2010
NAME: The Statistics of Poverty and Inequality
TYPE: Sample
SIZE: 97 observations, 8 variables
DESCRIPTIVE ABSTRACT:
For 97 countries in the world, data are given for birth rates, death
rates, infant death rates, life expectancies for males and females, and
Gross National Product.
SOURCES:
Day, A. (ed.) (1992), _The Annual Register 1992_, 234, London:
Longmans.
_U.N.E.S.C.O. 1990 Demographic Year Book_ (1990), New York: United
Nations.
VARIABLE...

...Key Synthesis/Potential Test Questions (PTQs)
• What is statistics? Making an inference about a population from a
sample.
• What is the logic that allows you to be 95% confident that the confidence interval contains the population parameter?
We know from the CLT that sample means are normally distributed around the real population mean (). Any time you have a sample mean within E (margin of error) of then the confidence interval will contain . Since 95% of the sample...

...
Investigating Bottling Company Case Study
T.P
University
Statistics
Mat 300
Mr. Thevar
December 01, 2013
Investigating Bottling Company Case Study
The case study that is being investigated is for a bottling company producing less soda than what is advertised. Customers have complained that the sodas in the bottles contain less than the advertised sixteen ounces. The employees at the company have measured the amount of soda contained in each bottle....

...H0: µ ≤ 3, H1: µ > 3
C H0: µ = 3, H1: µ ≠ 3
D H0: µ ≠ 3, H1: µ = 3
E None of the above
Ans: B
What is (are) the critical value(s)?
A -1.96 and 1.96
B -1.645
C -1.645 and 1.645
D 1.645
E None of the above
Ans: D
What is the calculated test statistic?
A 2.12
B 1.43
C 1.78
D 1.23
E None of the above
Ans: A
What is your conclusion? (choose the most correct answer)
A Reject Ho at the 5% level of significance.
B Accept Ho at the 5% level of...