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You work for a consumer watchdog publication and are testing the advertising claims of a light bulb manufacturer. The manufacturer claims that the life span of the bulb is normally distributed, with
Calculate point estimates of the population variance and the population standard deviation. Calculate the standard error of the point estimate found in part (a). Provide an interpretation of the stand
Generate a 95% confidence interval for the difference in mean HDL levels between men who exercise regularly and those who do not.
He measures the temperature at 36 various random locations, puts the data into a calculator and determines a mean of 65.3 and a standard deviation of 2.4 degrees. Construct a 95% confidence interval
A sample of 800 voters revealed that 52% of them would vote for a specific issue. Create and interpret a 95% confidence interval for the support of the issue. In the interpretation indicate what typ
What size sample will be needed to construct a 95% confidence interval on a ballot issue if the estimate must be ± 2% of the actual percent. This issue looks very close in the election.
Is there a statistically significant difference in ages of children assigned to the treatments? Apply the two sample z test at a 5% level of significance.
A researcher wonders if there is a difference in perfectionism across individuals who receive different amount of parental critism. She samples individuals and divides them into groups-no critism, w
Why is it important to specify the null and alternative hypothesis, along with the significance level, before the sample data is observed? ( More than one sentence please.
In a certain city 40% consider themselves Conservatives (C) 35% Liberals (L) and 25% Independents (I). During a particular election 45% of the conservatives voted 40% of the liberals voted and 60 %
Fred did a study to see if a psychiatric patients respond to a better to a certain kind of therapy. He arranged for patients to be randomly assigned to different therapy groups and monitored their d
Use this information to answer the next two questions. A researcher at a major hospital wishes to estimate the proportion of the adult population of the United States that has high blood pressure.
In 2010, 433,428 adult Texans were diagnosed with diabetes for the first time. What is the incidence of diabetes in Texas? Express your answer in units of per 1000 persons per year.
To compare two kinds of front-end design, six of each kind were installed on a certain make of compact car. Then each car was run into a concrete wall at 5 miles per hour, and the following are the
Which of the following is considered a decision variable in the media selection problem of minimizing interview costs in surveying?
Use the four steps of testing hypothesis at 0.05 level of significance to test the null hypothesis Musub1-Musub2=-0.5 against the altenative hypothesis Musub1-Musub2<-0.5.
Assume that customers arrive completely randomly, one at a time, at the rate of 15 per hour. Calculate the operating characteristics of interest to the manager.
The power of this test against the alternative hypothesis that the chance the die lands with one spot showing is 13.62%, the chance the die lands with six spots showing is 19.71%, and the chances th
In the 2012 Us census, the four most populous states (CA, TX, NY, FL) had 12.1%, 8.1%, 6.3% and 6.1% of the total US population. Suppose a pollster surveys 1000 US citizens and 102 are from CA, 84 f
A random sample of 6 music majors playing song S counted the number of mistakes each made. Then these musicians played song G and the mistakes were tallied. In between playing the two songs, the stu
Suppose the second survey had 20 subjects and a sample standard devation of 9 shots. Prob. Type I error = .05 Can we supprt the claim that the variation on the second day was greater than the variat
There is a tradeoff between the cost of eroneously discarding a good lot, and the cost of warranty claims if a bad lot is sold. The next few problems refer to this scenario.
Two airlines are randomly sampled to compare the porportion of on-time flights. out of 300 flights, 73% of the flights at A were ontime, while B had 82% of 250 flights on time. find a 95% confidence
A random sample of 22 cans from Y store had a mean of $12.03 and a standard deviation of $3.86. A random sample of 25 cans from Z store had a mean of $14.05 and a standard deviation of $4.02. probab
Jorge finds that his standardized z score on an IQ is 2.0. What percentage of people did he score higher than?