show your work please

final answers

-A consumer organization inspecting new cars found that many had appearance defects​ (dents, scratches, paint​ chips, etc.). While none had more than three of these​defects,

6​% had​ three, 12% had​ two, and 26% had one defect. Find the expected number of appearance defects in a new car and the standard deviation. Compute the expected value of the number of appearance defects.

​E(appearance

​defects)equals=. 68.68

​(Round to two decimal places as​ needed.)

Compute the standard deviation of the number of appearance defects.

​SD(appearance

​defects)equals= _____________________

​(Round to two decimal places as​ needed.)

-A salesman normally makes a sale​ (closes) on 70% of his presentations. Assuming the presentations are​ independent, find the probability of each of the following.​

a) He fails to close for the first time on his sixth attempt.​

b) He closes his first presentation on his fifth attempt.

​c) The first presentation he closes will be on his second attempt.

​d) The first presentation he closes will be on one of his first three attempts.

A manufacturer of game controllers is concerned that its controller may be difficult for​ left-handed users. They set out to find lefties to test. About 11% of the population is​ left-handed. If they select a sample of 99 customers at random in their​ stores, what is the probability of each of the outcomes described in parts a through f​ below?

​a) The first lefty is the third person chosen.The probability is _____________________

​(Round to four decimal places as​ needed.)

​b) There are some lefties among the 99 people.The probability is _______________________

​(Round to four decimal places as​ needed.)

​c) The first lefty is the second or third person. The probability is __________________________

​(Round to four decimal places as​ needed.)

​d) There are exactly 3 lefties in the group. The probability is __________________________

​(Round to four decimal places as​ needed.)

​e) There are at least 3 lefties in the group. The probability is __________________________

​(Round to four decimal places as​ needed.)

​f) There are no more than 3 lefties in the group. The probability is _________________________

​(Round to four decimal places as​ needed.)

Show your work please

final answers

Two fair dice are tossed together. Let X be the sum and Y the product of the two numbers on the top of the dice. Calculate E(X+ 3Y).

Show your work please

A random sample of 20 aluminum cola cans is selected and the axial loads are measured and the variance is 345.96 lb. Use a 0.05 significance level to test the claim that cans have axial loads with the smaller variance than 772.84 lb.

final answers

The mean annual salary offer for a student graduating with a degree in accounting (in 2010) was $48,722.

Suppose that a randomly selected sample of 20 accounting graduates shows an average salary offer of $49,850 with a standard deviation of $3300.

A. How many degrees of freedom are there for the t distribution?  

B. Assume that the population distribution is normal. What is the value of the test statistic, t? Give your answer to two decimal places.

C. If we use a significance level of 0.05, what is the critical value of t? (Hint: Use the attached table. Is this for a one-sided or two-sided test?)  

A group of 9 friends includes 4 Americans, 2 Canadians, and 3 Italians. Three friends are to be selected at random for a trip. Let X denote the number of Americans and Y be the number of Canadians selected at random among the three friends selected for a trip.

1) Find the joint probability density function of the random variables X and Y and the marginal density functions.

2) Find Cov(2X-1, -Y+1).

A sample of size n = 16 is made from a normal distribution with mean μ. It
turns out that the sample mean is x = 23 and the sample standard deviation is s = 6.
Construct a 90% confidence interval for μ.

A study was conducted to find out if eating whole-wheat products was associated with a reduction
in body mass index (BMI) in adults. Researchers randomly assigned participants into two groups
(eaters and non-eaters of whole-eat products) for a two-month period. The average BMI reduction
for the 155 adults who ate whole-wheat products was 2.3 and the standard deviation was 1.1.
For the 148 adults who did not eat whole-wheat products the average BMI reduction was 1.2 and
the standard deviation was 0.8. Considering a level of significance of 0.05 (5%), build a test of
hypotheses to assess whether the average reduction in BMI would be different between eaters and
non-eaters of whole-wheat products for the population of adults similar to the ones in this study.
a) Is this a one-sided or a two-sided test? Why?
b) Specify all four steps of your hypothesis test. Show all calculation detail

The admission office wants to estimate the mean age of all students enrolled at ZU. The estimate must be within half year of the population mean. Assume the population of ages is normally distributed.  Also assume that the population standard deviation is 1.4 years.

1- Determine the minimum sample size required to construct a 90% confidence interval for the population mean ?....

2-Repeat part (a) using a 99% confidence interval ? .....

  3-Which level of confidence requires a larger sample size? Explain ....

2.

Complete the problems below.

a. A sample 81 desktop PCs have a mean lifespan of 7.5 years and a sample standard deviation of 3.2 years. Construct a 99% confidence interval for the mean lifespan of desktop PCs.(ROUND TO 3 DECIMAL PLACES)

Confidence Interval ( ___________________Q6 , ___________________Q7)

b. When consumers apply for credit, their credit is rated using FICO scores. Credit ratings are given below for a sample of car loan applicants. Use the sample data to construct a 99% confidence interval for the mean FICO score of all applicants for credit.

(ROUND TO THE NEAREST WHOLE NUMBER) assume requirements are fulfilled.

661 595 548 730 791 678 672 491 492 583 762 624 769 729 734 706

Confidence Interval ( ___________________Q8 , ___________________Q9)

c. The IQ scores of the normal adult population has a mean of 100 IQ points and the standard deviation is 15 IQ points.

Find the sample size needed to estimate the mean IQ of professors given we want 93% confidence that the sample mean is within 4 IQ points of the population

mean.

(USE YOUR ANSWER FROM PROBLEM #1a for critical value).

n=_____________Q10

1) What is the value of b1? X: 12, 21, 28, 8, 20. Y: 17, 15, 22, 19, 24

2) What is the value of b0? X: 12, 21, 28, 8, 20. Y: 17, 15, 22, 19, 24

3) What is the equation of the y-hat estimator line? X: 12, 21, 28, 8, 20. Y: 17, 15, 22, 19, 24.

a. Y=0.162-16.51x b. y=0.162+16.51x c. Y=16.51-0.162x d. Y=16.51+0.162x

4) If x is increased by 10 units, how much does y-hat change?

5) Assume b0=12.953, and b1=-2.5. For x=25, predict y.

6) How much correlation is there between x and y? X: 12, 21, 28, 8, 20. Y: 17,15, 22, 19, 24.

7) How much of the variability in y is explained by x? X: 12, 21, 28, 8, 20. Y: 17, 15, 22, 19, 24.

8) Executives of a video rental chain want to predict the success o a potential new store. The company's researcher beings by gathering information on number o rentals and average family income from several of the chain's present outlets. The results of that effort are available in the attached data file.

rentals: 710, 529, 314, 504, 619, 428, 317, 205, 468, 545, 607, 694.  

Average family income ($1,000): 65, 43, 29, 47, 52, 50, 46, 29, 31, 43, 49, 64

a. y=10.626+9.729x b. y=9.729+10.626x c. y=10.626-9.729x d. y=-9.729-10.626x

9) Following Question 8, How much correlation exists between x and y?

10)Following question 8, How much of the variation in y is accounted for by x?

The motion picture industry is a competitive business. More than 50 studios produce several hundred new motion pictures each year, and the financial success of the motion pictures varies considerably. The opening weekend gross sales, the total gross sales ($ millions), the total gross sales ($millions), the number of theaters the movie was shown in, and the number of weeks the motion picture was in release are common variables used to measure the success of a movie. Data on the top 100 grossing motion pictures released in 2016 (Box Office Mojo website) are contained in a file named Movies2016. Table 3.10 below shows the data for the first 10 motion pictures in this file.

Use the numerical methods of descriptive statistics presented in this chapter to learn how these variables contribute to the success of a motion picture. Include the following in your report:

1. Descriptive statistics for each of the four variables along with a discussion of what the descriptive statistics tell us about the motion picture industry.

2. What motion pictures, if any, should be considered high-performance outliers? Explain.

3. Descriptive statistics showing the relationship between total gross sales and each of the other variables. Discuss.

Find critical value t_α/2 for n = 15 and 98% confidence level.

A.±2.6245

B.±2.4142

C.±2.4460

D.±2.5551