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. Researchers asked a random sample of 390 new pet owners if they would consider purchasing pet health insurance.  The confidence interval for a [prop] should be constructed because the variable of interest is [var] and this is [qual].

A poll was conducted asking employees and students at a large college, “Do you believe that there is enough parking available at the college?”  In a random sample of 150 employees, 87 believed that there was enough parking.  In a random sample of 320 students, 150 believed that there was enough parking.  Assume that the conditions are met to construct a confidence interval.  Choose the best answer in each case.  Where rounding is necessary round to three decimal places.  1. What is the point estimate of the difference in the proportions of employees and students that believe that there is enough parking at the college?  [pt] 2. Find the 95% confidence interval for the difference in the proportions of employees and students that believe that there is enough parking.  We are 95% confident that the difference in the proportions of employees and students that believe that there is enough parking is between [lower] and [upper]. Since the interval [is] we [conclude]. 

A hypothesis test is constructed so that the null and alternative hypotheses have the following meanings: Ho:  the weather stays dry (no rain) H1:  it rains You are trying to decide whether to bring your rain boots with you today in case it does rain.  Which of the following represent a Type 1 and Type 2 error in this scenario?

Sleep patterns of 6 month old infants are studied.  A researcher measures the sleep time of a random sample of 6 month old infants, recording the hours of sleep over a 24 hour period.  Assume that the sleep times are normally distributed.  Find the 95% confidence interval based on the provided data.   All values are given in hours.  Round the endpoints to one decimal place.  13.3     12.8     12.6     14.3     13.3     12.6     12.8     12.2     12.7     12.7     12.2

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. Researchers asked a random sample of 1054 college students if they believed that they would be able to buy their own home within the next 12 years, yes or no.  The confidence interval for a [prop] should be constructed because the variable of interest is [var] and this is [qual].

A survey of 2304 randomly chosen American Adults found that 765 of them had donated blood in the last three years.  A hospital wants to construct a 95% confidence interval for the proportion of all American Adults who have given blood in the last three years.    a. What is the point estimate of the proportion of American Adults that have given blood in the last three years?  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 given blood in the last three years.  Round to three decimal places.  Choose the best answer.   [answere]  

An SMC student wants to determine the mean amount of financial aid received by students at the college.  How many students should be polled to determine the mean to within $85 at 95% confidence.  Assume that the standard deviation in financial aid is known to be $1500.  

Suppose you want to find a confidence interval at a confidence level of 84%. What is the corresponding critical value,

A certain college is concerned about grade inflation and decides to include z-scores along with letter grades for each class.  Suppose a certain student takes three classes.  The table below gives the students score in each class, along with the mean and standard deviation of the scores in each class.   Subject Student’s score Mean  Standard deviation  z-score Math  83 75.1 6.4 [math] English 78 70 2.9 [eng] History 92 84 5.7 [his] 1. Complete the table by finding the z-score for each class.  If rounding is necessary, round to two decimal places.  2. Complete the following sentence:  Relatively speaking the student did the best in [subj] because [reason]

When the liquid outside the cell is equal in electrolytes as the inside, it is known as: