#### Statistic

**Paper , Order, or Assignment Requirements**

Marion A. Baptiste

Statistic Exam

When the owner of a small business reviews her list of contract for 2011, she finds that 35% of the contracts were from clients she met at a large conference at the end of 2010. Answer the following questions about this situation.

a. Was the measurement obtained by a sample or a census? What words in the description of the situation make you confident that your answer is correct?

b. Should the owner have taken into account some measure of reliability associated with the value of 35%

Assume that the number of sales per day of an app in the Apple IOS App store is normally distributed.

a. What two parameters of the distribution would you need to be able to determine the probability of sales on a particular day exceeding 100 units?

b. If the probability of sales exceeding 100 units is 20% and the mean daily sales is 86 units, then what is the standard deviation of the distribution?

A health inspector at a restaurant will enter the kitchen and choose 5 situations to inspect from a predetermined list of 15 stations present in most restaurant kitchens.

a. How many different sets of 3 exist?

b. If all sets are equally likely, what is the probability of each set?

c. If the inspector were instead, to randomly select 13 stations to inspect, how many different sets of 13 stations would exist?

d. If all sets were equally likely. What is the probability of each set?

A quality control analyst measures the number of hours a patient in a low-risk condition waits for care at the emergency room of a small hospital. The following data are obtained for 20 patients

2.26 2.01 3.0 1.22 1.79 0.78 1.89 0.71 1.58

2.02 2.77 2.87 0.51 0.74 1.95 2.76 2.61 3.54 2.95

a. Compute the sample mean, sample median, and range of the data.

b. Compute the sample standard and sample variance.

Consider the following data values of variable x and y

X 5 4 3 6 9 8 10

Y 7 8 10 5 2 3 1 – construct a scatter diagram of the data points and plot the least squares regression line on it. Find the least squares regression line.

A quality control experiment is to be done on a machine that fills tubes with tooth paste. Its specifications require that it fill tubes with 4.7oz. A random sample of 40 tubes filled by the machine is taken and each tube is weighed. The resulting data are below, with the weight of the tube already having been subtracted from each. Perform a hypothesis test at the 90% confidence level to determine if the machine is performing according to the specifications.

4.66 4.61 4.71 4.63 4.70 4.62 4.63 4.61 4.70 4.56

4.60 4.66 4.68 4.57 4.67 4.72 4.67 4.64 4.66 4.75

4.69 4.64 4.67 4.65 4.69 4.65 4.75 4.53 4.57 4.74

4.68 4.67 4.66 4.68 4.64 4.65 4.64 4.80 4.71 4.69