Determine whether the sampling is independent or dependent and whether the variable is qualitative or quantitative.  A psychologist wants to measure the effect of music on relaxation.  He random selects 75 volunteers and measures their stress level in silence and then again with the same volunteers the next day while music is playing.   The mean score without music is compared to the mean score with music.

Identify the level of measurement (nominal, ordinal, interval, ratio) for each of the following variables.  a. Temperature of a cup of coffee [cof] b. Height of a 6-year old in inches [hei] c. Color of a car [car] d. Size of a rental car: subcompact, compact, standard, full-size [size]

Which of the following will decrease the width of a confidence interval?

For the​ following, indicate whether a confidence interval for a proportion or mean should be constructed to estimate the variable of interest. Justify your response. Does caffeine intake affect resting heart rate?  A researcher asks 175 women to decrease their caffeine intake by 200 mg per day for two weeks and then records the change in their resting heart rate.  The confidence interval for a [mena] should be constructed because the variable of interest is [var] which is [quant].

A marketing firm wants to compare the proportion of those who say they are regular viewers of reality TV in the 20-29 year and 30-39 year age groups.  In a random sample of 150 people aged 20-29, 49 said they are regular viewers of reality TV.  In a random sample of 200 people aged 30-39, 56 said they are regular viewers of reality TV.  At the 0.05 level of significance test to determine if the proportion is higher in the 20-29 age group.  Assume that the conditions to complete the hypothesis test are met.  1) What is the correct null and alternative hypothesis?  Choose from the options below.  [answer1]                                   a.     H0: 

A survey of 2300 randomly chosen American Adults found that 604 agreed that they had experienced insomnia in the last month.  Use this information to complete the following to find the corresponding 95% confidence interval. a. What is the point estimate of the proportion of American Adults that have experienced insomnia in the last month?  Round to three decimal places.  [answera] b. Does the sample meet the conditions to calculate the confidence interval for the proportion?           [answerb] because the sample is random, the sample is less than 5% of the population and [answerc]. c.  Use the appropriate formula to find the margin of error, rounded to three decimal places.  Remember to round off only at the end.  [answerd] d. Using the margin of error and point estimate from the above questions, find the 95% confidence interval for the proportion of American Adults who have experienced insomnia in the last month.  Round to three decimal places.  Choose the best answer.   [answere]  

Use the t-table to determine the critical value for a left tailed hypothesis test with a level of significance of 0.02.  The sample size is n = 94. 

A researcher wants to compare the proportion of residents of California who have visited a national park to the proportion of residents of Florida who have visited a national park.  A sample of 570 residents of California indicated that 27% of the sample had visited a national park.  A sample of 620 residents of Florida indicated that 24% of the sample had visited a national park.  At the 0.05 level of significance, test the claim that the proportion of residents of California who have visited a national park is greater than the proportion of residents of Florida who have visited a national park.   1) What is the correct null and alternative hypothesis?  Choose from the options below.  [answer1]                                   a.     H0: 

A study was done to determine the mean number of pets per household in a certain city. For the 60 households surveyed, the sample  was mean 2.1 pets and the sample standard deviation was 0.7 pets.  The distribution to use to calculate the 95% confidence interval is ________________.  

A study is done to determine the mean time that it takes an order to be filled at a drive-thru window.  The fulfilment times for 500 customers at a drive-thru window are recorded and this results in a 90% confidence interval of 92.4 seconds to 96.3 seconds. Which of the following best expresses the meaning of this confidence interval?