Deck 9: Statistical

Question 1

What is meant by the phrase: the central tendency of the data? How are these values used?

Answer 1

The central tendency of the data is where the data is grouped or gathered. Determining where the data is concentrated, by using the mean, mode, and median, helps those studying a process or product determine the gap between the desired target and what the process is producing.

Question 2

Describe how the mean, mode, median, range and standard deviation work together to describe the data presented in a histogram.

Answer 2

The mean, mode, and median describe the central tendency of the data or where the data is centered. The standard deviation and range are the measures of dispersion describing how widely the data is spread. Both are necessary to determine how much variation is present in the process and where the process is performing in relation to the target.

Question 3

What is meant by the phrase: measures of dispersion? How are these values used?

Answer 3

Measures of dispersion, the range and standard deviation, refer to the spread of the data. The range and standard deviation enable those studying a process to understand how much variation is present in the process.

Question 4

Calculate the mean, mode, and median of the following information: 48.1, 48.2, 48.1, 48.3, 48.4, 48.5, 48.1, 48.3.

Question 5

To create a paper clip, wire is cut to 4 " lengths and then formed into the shape we are all familiar with. Use the following information to create a histogram. Show all formulas and appropriate calculations.

Question 6

If the mean value of the weight of a particular brand of dog food bag is 20.6 pounds and the standard deviation is 1.3, assume a normal distribution and calculate the percentage of bags that falls below the lower specification value of 19.7 pounds.

Question 7

Calculate the mean, range, and standard deviation of the following numbers: 300, 440, 275, 350. Calculate the mean, range, and standard deviation of these numbers: 350, 470, 300, 360.

Question 8

A company has been studying the performance of their sales department. The measure of performance used is: average monthly sales amount in dollars. For the past 12 months, the average monthly sales amount has been $4,532 with a standard deviation of $386. Calculate the percentage of months that the average monthly sales amount exceeds $5,800.

Question 9

One of the dimensions measured when filling bottles of olive oil is the depth of the cork in the bottle. Since the depth of the cork in the bottle affects the size of the air gap in the bottle, this dimension is critical. Its specification is 48.5 +/- 0.5 mm. During a recent day, 35 bottles were inspected for the depth of the cork in the bottle. Create and interpret a histogram using the following information.