A confidence interval is an interval estimate of ___________.

A forest management team chooses  a random sample of silver maple trees and measures their diameters (in inches) and records the age of each tree in years.  The information is summarized in the following table.   Diameter (x) in inches Age (y) in years 3.9 11.7 11.4 35.3 5.3 14.8 7.6 18.0 6.6 19.8 8.6 23.9 4.4 14.3 3.2 11.8 6.5 19.5 1. Find the linear correlation coefficient r for this data set.  Round to three decimal places. [r] 2. A hypothesis test is to be done to determine if there is linear correlation between these two variables.  The null and alternative hypotheses are given below.  Use a 0.05 level of significance.          

A certain medication is known to cause side effects in 20% of the patients that take the medication.  A doctor prescribes the medication to 6 unrelated patients.  What is the probability that none of them develop side effects?  If rounding is necessary, round to decimal places. 

Determine the level of measurement for each of the following variables. The number of photos taken by a person on vacation. [level1] The rating system of hot sauce as mild, medium, spicy. [level2]

Consider the two normal curves pictured above.  Which of the following is a true statement for this graph. 

When a confidence interval has a confidence level of 95%, which of the following gives the meaning of the “95%?”

A study was conducted to determine if the salaries of librarians from two neighboring states were equal. Asample of 200 librarians from each state was randomly selected. The mean from the first state was $69,100 witha standard deviation of $2500. The mean from the second state was $70,500 with a standard deviation of $2300.Find the 95% confidence interval for the difference in the mean salary for a librarian from these two states. Round to the nearest dollar and use only methods from class.  1. Are these considered dependent or independent populations?  [dep] 2. What is the point estimate of the mean difference?  [point] 3. We are 95%confident that the difference in the mean difference in the librarian salaries between the first and second state is between [lower] and [upper]. 4. Because the interval [is] we [conclude].   

The data set below represents the calories in a sample of 10 blueberry muffins. 467   410   355   372   390   501   420   290   440   250 Find each of the following for this data set.  Where rounding is necessary, round to one decimal place.  Mean = [mean] calories standard deviation = [sd] calories Q1= [Q1] calories Median = [med] calories Q3=[Q3] calories IQR = [IQR] calories Values outside of the interval [unusual] would be considered unusual. Values outside of the interval [outlier] would be considered outliers. 

A confidence interval is to be constructed to determine the mean amount of time that a student spends watching television each weekend.  The sample size is 100 and the confidence level is 95%.  If everything else stays the same, which of the following statements is true if the confidence level is changed to 90%?

It is found that there is a strong linear relationship between the number of hours per week that a student spends commuting (x) and the time spent studying per week (y), for