Exam 12: Inference About a Population

After calculating the sample size needed to estimate a population proportion to within 0.04,your statistics professor told you the maximum allowable error must be reduced to just .01.If the original calculation led to a sample size of 800,the sample size will now have to be:

In a hypothesis test for the population variance,the hypotheses are H₀: $\sigma$ ² = 100 vs.H₁: $\sigma$ ² $\neq$ 100.If the sample size is 15 and the test is being carried out at the 10% level of significance,the rejection region is:

The statistic (n - 1)s² / $\sigma$ ² has a chi-squared distribution with n - 1 degrees of freedom if:

Which of the following statements is false?

For statistical inference about the mean of a single population when the population standard deviation is unknown,the degrees for freedom for the t-distribution equal n -1 because we lose one degree of freedom by using the:

Which of the following statements is correct regarding mass marketing?

Concert Tickets A simple random sample of 100 concert tickets was drawn from a normal population.The mean and standard deviation of the sample were $120 and $25,respectively. -{Concert Tickets Narrative} Estimate the population mean with 90% confidence.

When the population standard deviation is unknown and the population is ____________________,the test statistic for testing hypotheses about $\mu$ is the t-distribution with n - 1 degrees of freedom.

The sum of squared deviations from the mean divided by the population variance has a(n)____________________ distribution with ____________________ degrees of freedom.

In order to interpret the p-value associated with hypothesis testing about the population mean $\mu$ ,it is necessary to know the value of the test statistic.

Researchers determine that 60 Puffs tissues is the average number of tissues used during a cold.Suppose a random sample of 100 Puffs users yielded the following data on the number of tissues used during a cold: $\bar { x }$ = 52 and s = 22.Using the sample information provided,the value of the test statistic is:

Mass Marketing refers to the mass production and marketing by a company of a single product for the entire market.

The t-distribution is used in a confidence interval for a mean when the actual standard error is not known.

Generally speaking,mass marketing has given way to target marketing,which focuses on satisfying the demands of a particular segment of the entire market.

Target marketing focuses on satisfying the demands of all segments of the entire market.

Healthy Foods In segmenting the frozen meal market in Spain,a food manufacturer uses health and diet consciousness as the segmentation variable.Four segments are developed and coded as follows: 1: Concermed about eating healthy faods 2: Concerned about weight 3: Concerned about health because of illnese 4: Unconcermed To distinguish between groups,surveys are conducted.On the basis of a questionnaire,people are categorized as belonging to one of these groups.A recent survey asked a random sample of 1,500 Spanish adults (20 and over)to complete the survey.Out of the 1,500 people surveyed,360 indicated that they are concerned about eating healthy foods.The most recent information available reveals that there are 40,256,000 Spanish adults who are 20 and over. -{Healthy Foods Narrative} Estimate with 95% confidence the proportion p of Spanish adults who classify themselves as concerned about eating healthy.

In determining the sample size needed to estimate the population proportion p,we let the sample proportion $\hat { P }$ = 1 if we have no knowledge of even the approximate values of $\hat { P }$ .

Assuming that all necessary conditions are met,what needs to be changed in the formula $\hat { p } \pm t _ { \alpha } \sqrt { \hat { p } ( 1 - \tilde { p } ) / n }$ so that we can use it to construct a (1 - $\alpha$ )confidence interval estimate for the population proportion p?

Sinus Drug A company claims that 10% of the users of a certain sinus drug experience drowsiness.In clinical studies of this sinus drug,81 of the 900 subjects experienced drowsiness -{Sinus Drug Narrative} Construct a 95% confidence interval estimate of the population proportion of the users of this allergy drug who experience drowsiness.

Pilots' Union Contract A union composed of several thousand pilots is preparing to vote on a new contract.A random sample of 500 pilots yielded 320 who planned to vote yes.It is believed that the new contract will receive more than 60% yes votes. -{Pilots' Union Contract Narrative} Can we infer at the 5% significance level that the new contract will receive more than 60% yes votes?