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:

The confidence level for a confidence interval is changed from 95% to 99%.  Assume that all other conditions remain the same. What is the effect on the width of the interval, if it can be determined.  If not, why not. 

If the consequences of making a Type I error are​ severe, would you choose the level of​ significance,

A sea otter in the wild has a mean lifespan of 13.8 years with a standard deviation of 3.8 years.  Assume that these lifespans are bell-shaped.  1. Approximately 97.5% of sea otters live at least [ans1] years. 2. Approximately [ans2] of sea otters live between 6.2 to 10  years. 3.If a random sample of 200 sea otters in the wild is chosen, we’d expect about [ans3] to live less than 10 years.  4. Approximately [ans4] of sea otters live at least 17.6 years. 

The organ system that includes specialized glands that produce hormones is the ____________system: