ISE Principles of Statistics for Engineers and Scientists 2nd. Edition by William Navidi Prof. | 9781260570731 | 1260570738

ISE Principles of Statistics for Engineers and Scientists

1 SOLVED PROBLEMS

183 SOLVED PROBLEMS

Question: 4.31

At a large university, the mean age of the students is 22.3 years, and the standard deviation is 4 years. A random sample of 64 students is drawn. What is the probability that the average age of these students is greater than 23 years? ...

Verified Answer:

Let

X_1 .... X_{64}

be the ages of ...

Question: 4.4

According to a 2016 report by J.D. Power and Associates, approximately 20% of registered automobiles have been recalled for a manufacturer’s defect but have not been repaired. Twelve automobiles are sampled at random. What is the probability that fewer than four of them have been recalled but not ...

Verified Answer:

Let X represent the number of automobiles in the s...

Question: 4.5

Refer to Example 4.4. What is the probability that more than 1 of the 12 cars has been recalled but not repaired? ...

Verified Answer:

Let X represent the number of cars that have been ...

Question: 5.21

A sample of 10 concrete blocks manufactured by a certain process had a mean compressive strength of X = 1312 MPa, with standard deviation s = 25 MPa. Find a 95% prediction interval for the strength of a block that has not yet been measured. ...

Verified Answer:

For a 95% prediction interval, 𝛼 = 0.025. We have ...

Question: 5.22

The lengths of bolts manufactured by a certain process are known to be normally distributed. In a sample of 30 bolts, the average length was 10.25 cm, with a standard deviation of 0.20 cm. Find a tolerance interval that includes 90% of the lengths of the bolts with 95% confidence. ...

Verified Answer:

We have

\overline{X} = 10.25

and s ...

Question: 6.9

Use the data in Table 6.2 to test the null hypothesis that the proportions of pins that are too thin, OK, or too thick are the same for all the machines. ...

Verified Answer:

We begin by using Equation (6.5) to compute the ex...

Question: 8.10

In a study of the relationship between the permeability (y) of human skin and its electrical resistance (x), the data presented in the following table were obtained for 50 skin specimens, each 2.54 cm² in area. Here permeability is measured in 𝜇m/h and resistance is measured in kΩ. Using a linear ...

Verified Answer:

We calculate the following quantities:

\ove...

Question: 8.11

Refer to Example 8.10. Let 𝜇0 represent the mean permeability of skin whose resistance is 15 kΩ. Test H0 : 𝜇0 ≤ 9 versus H1 : 𝜇0 > 9. ...

Verified Answer:

Since

\mu_{0}

is the mean permeabil...

Question: 9.3

For the data in Table 9.1, compute MSTr, MSE, and F. Find the P-value for testing the null hypothesis that all the means are equal. What do you conclude? ...

Verified Answer:

From Example 9.2, SSTr = 743.4 and SSE = 1023.6. W...

Question: 9.6

The following output (from MINITAB) presents the ANOVA table for the weld data in Table 9.1 (in Section 9.1). Which pairs of fluxes, if any, can be concluded, at the 5% level, to differ in their effect on hardness? ...

Verified Answer:

There are I = 4 levels, with J = 5 observations at...

Question: 10.11

The design specifications for a piston rod used in an automatic transmission call for the rod length to be between 71.4 and 72.8 mm. The process is monitored with an X chart and an S chart, using samples of size n = 5. These show the process to be in control. The values of X and s are X = 71.8 mm ...

Verified Answer:

We estimate 𝜇̂ =

\overset{=}{X} = 71.8[/lat...