Exam 11: Statistics

Draw a scatter plot and describe the relationship.

The average amount customers at a certain grocery store spend yearly is $732.15. Assume the variable is normally distributed. If the standard deviation is $51.91, find the probability that a randomly selected customer spends less than $742.53.

These data represent the grades on a college exam. Find the mean

Draw a scatter plot and describe the relationship.

Consider the survey question "Are you going to vote for Candidate Jones, even though the latest Survey shows he will lose the election?" Why do you think the question is a poor one?

The average amount customers at a certain grocery store spend yearly is $635.55. Assume the Variable is normally distributed. If the standard deviation is $94.41, find the probability that a Randomly selected customer spends between $569.46 and $758.28.

Last year's total attendance at Long Run High School's football games was 8,325. Decide whether Descriptive or inferential statistics is being used.

Find the range, variance, and standard deviation for the given data. The table below shows the Average points scored per game by several intramural softball teams. Round to one decimal place.

Determine whether a correlation coefficient of r = 0.091 is significant at the 5% level for a sample Size of 120.

A standardized test of intelligence is scaled so that the mean IQ is 100, and the standard deviation is 15. On a standardized IQ test, what is the Z score for a person with an IQ of 145?

A sample is one where members of a preexisting group are selected.

Find the area under the normal distribution curve to the left of z = -1.15.

These data represent the number of gas stations along a certain 50-mile length of desert road. Draw a time series graph for the data.

Draw a scatter plot for the data shown.

The graphs below display the average life expectancy for Americans according to the National Center for Health Statistics. Which graph would you show if you wanted to convince someone that the advances of modern medicine will soon have us living to be 150?

To obtain the frequency distribution below, twenty-three babies were monitored for how many times they cried during the night. Construct a histogram and frequency polygon for the data.

Fran's percentile rank on an exam in a class of 500 is 85. Kelly's class rank is 60. Who is ranked Higher?

Normal distributions are very commonly used for quality control in manufacturing. For example, a Manufacturer of light bulbs would surely be interested in studying how long their bulbs last. In one Case, the lifetime of one model of light bulb is normally distributed and has a mean X = 1,900 hours And a standard deviation of s = 250 hours. What is the probability that a bulb will last between 1,650 And 1,900 hours?

Suppose the average size (in square feet)of homes in a certain region is 2,869. Assume the variable Is normally distributed with standard deviation 100. If a person in the region was intending to build A 3,099 square foot home but downsized and built a 2,794 square foot home, what was the change in Percentile rank from the original plan to the actual home that was built?

When a population is divided into groups where the members of each group have similar characteristics and a certain number of members from each group are chosen at random, the result is called a sample.