Exam 2

Question 1

If the plating time of a tube increases as the inside diameter decreases, then the correlation coefficient for the inside diameter versus plating time would be

Answer 1

Between 0 and 1

Question 2

How is the level of significance defined?

Answer 2

The probability of rejecting a null hypothesis when it is true

Question 3

A randomly selected sample of bicycle helmets was tested for impact resistance. Given the data results below, what is the 95% confidence interval for the mean? Test results: sample size = 100 helmets, average impact resistance = 276 g, standard deviation = 15 g

Answer 3

276 + or - 2.94 g

Question 4

A p-value is used in many statistical calculations.it can be described as:

Answer 4

Containing an extreme test statistic probability value as obtained from the sampling data

Question 5

From a statistical standpoint, the sample size for hypothesis testing depends on

Answer 5

The required type 1 and type 2 risks

Question 6

Non-value added activities on the factory floor are most clearly controlled by the elimination of

Answer 6

Muda

Question 7

Which of the following statements concerning the coefficient of simple linear correlation, r, is true?

Answer 7

R= 0.76 has the same predictive power as r= - 0.76

Question 8

The correlation coefficient for test #1 equals 0.89, and the correlation coefficient for test #2 equals 0.79. Assuming the tests are in different subject areas, which is true?

Answer 8

Both tests show a strong correlation

Question 9

In order to calculate the confidence interval for the mean for a small sample, what must be known?

Answer 9

The average, standard deviation, and appropriate t value

Question 10

Which of the following statements concerning statistical inference is true?

Answer 10

The confidence interval is a range of values which may include the true population value

Question 11

What is the principle advantage of multi- vary charting?

Answer 11

It assists in the break down of components of variation

Question 12

A string tension gauge is used to validate settings on a tennis racket stringing machine. What are the 90% confidence limits for the estimated true value of the string tension?

Measurements: 57 pounds, 56 pounds, 60 pounds, 62 pounds, 55 pounds, and 59 pounds

Answer 12

Average= 58.1667
Za/2=1.645
60,34, 56.0

Question 13

Given a coefficient of determination of 0.85, which of the following is true?

Answer 13

85% of the variability is explained by the regression model

Question 14

The opposite of alpha risk in hypothesis testing is called:

Answer 14

Level of confidence

Question 15

A small change truly exists between a current process and an experimental process. However, an insufficient sample size is collected to determine the difference. What type of error would result?

Answer 15

A type 2 error

Question 16

What is the z-value needed to conduct a two tail test in a statistical inference problem, specifying a 90% confidence?

Answer 16

1.65

Question 17

A correlation coefficient of +0.95 for two variables, X and y, means that

Answer 17

There is a strong linear relationship between X and y

Question 18

If the 90% confidence for the mean is 181.3 to 203.8, which of the following statements is true?

Answer 18

None of the above

Question 19

The probabilistic regression model for any particular observed value of y contains a term beta knot,which represents

Answer 19

The y-axis intercept, when x=0

Question 20

For a linear correlation, the total sum of squares equals 1600, and the total sum of squared errors equals 1000. What is r-squared?

Answer 20

0.375