An article contained the following observations on degree of polymerization for paper specimens for which viscosity times concentration fell in a certain middle range:

420 425 427 427 432 433 434 437 439 446 447 448 453 454 465 469

Suppose the sample is from a normal population.

(a) Calculate a 95% confidence interval for the population mean, and interpret it.

(b) Calculate a 95% upper confidence bound for the population mean, and interpret it.

Experience (EXP) is positively associated with earnings (EARN), and years of schooling (S) is positively associated with earnings. Also, suppose that EXP and S not correlated. If a researcher estimates the regression :
log(EARNINGS) = β₁ + β₂EXP + u, the estimated coefficient on b₂ will be?

A. unbiased

B. None of these answers are correct.

C. overestimate the effect of EXP on earnings.

D. underestimate the effect of EXP on earnings.

The amounts of time per workout an athlete uses a stairclimber are normally​ distributed, with a mean of 24 minutes and a standard deviation of 5 minutes. Find the probability that a randomly selected athlete uses a stairclimber for​ (a) less than 20 ​minutes, (b) between 24 and 32 ​minutes, and​ (c) more than 40 minutes

The data in the accompanying table represent the heights and weights of a random sample of professional baseball players. Complete parts ​(a) through ​(c) below.

Player   Height_(inches)   Weight_(pounds)
Player_1   75   227
Player_2   75   195
Player_3   72   180
Player_4   82   231
Player_5   69   185
Player_6   74   190
Player_7   75   228
Player_8   71   200
Player_9   75   230

​(a) Draw a scatter diagram of the​ data

​(b) Determine the​ least-squares regression line. Test whether there is a linear relation between height and weight at the α=0.05 level of significance.

Determine the​ least-squares regression line. Choose the correct answer below.

A.

ŷ =−93.9x+4.058

B.

ŷ =4.058x−93.9

C.

ŷ =4.058x−95.9

D.

ŷ =8.058x−93.9

Test whether there is a linear relation between height and weight at the α=0.05 level of significance.

State the null and alternative hypotheses. Choose the correct answer below.

A.

H0​: β1=0

H1​: β1>0

B.

H0​: β0=0

H1​: β0≠0

C.

H0​: β1=0

H1​: β1≠0

D.

H0​: β0=0

H1​: β0>0

Determine the​ P-value for this hypothesis test.

​P-value=__?__

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

State the appropriate conclusion at the α=0.05 level of significance. Choose the correct answer below.

A.

Reject H0.

There is sufficient evidence to conclude that a linear relation exists between the height and weight of baseball players.

B.

Reject H0.

There is not sufficient evidence to conclude that a linear relation exists between the height and weight of baseball players.

C.

Do not reject H0.

There is not sufficient evidence to conclude that a linear relation exists between the height and weight of baseball players.

D.

Do not reject H0.

There is sufficient evidence to conclude that a linear relation exists between the height and weight of baseball players.

​(c) Remove the values listed for Player 4 from the data table. Test whether there is a linear relation between height and weight. Do you think that Player 4 is​ influential?

Determine the​ P-value for this hypothesis test.

​P-value=__?__

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

State the appropriate conclusion at the α=0.05 level of significance. Choose the correct answer below.

A.

Reject H0.

There is sufficient evidence to conclude that a linear relation exists between the height and weight of baseball players.

B.

Do not reject H0.

There is not sufficient evidence to conclude that a linear relation exists between the height and weight of baseball players.

C.

Do not reject H0.

There is sufficient evidence to conclude that a linear relation exists between the height and weight of baseball players.

D.

Reject H0.

There is not sufficient evidence to conclude that a linear relation exists between the height and weight of baseball players.

Do you think that Player 4 is​ influential?

No

Yes

Using your F Table, what is the critical value for a set of sample data that has a df between of 3 and a df within of 10, using a significance level of 0.05?

Suppose X is a normal random variable with μ = 350 and σ = 40. Find the values of the following probabilities. (Round your answers to four decimal places.)

(a) P(X < 468)

(b) P(390 < X < 454)

(c) P(X > 390)

Find the value of the probability of the standard normal random variable Z corresponding to this area. (Round your answer to four decimal places.) P(−1.68 < Z < 1.23) =?

Exam grades: Scores on a statistics final in a large class were normally distributed with a mean of

70 and a standard deviation of 10. Use the TI-84 PLUS calculator to answer the following. Round the answers to at least two decimals.

(a) Find the 42nd percentile of the scores.

(b) Find the 71st percentile of the scores.

(c) The instructor wants to give an A to the students whose scores were in the top 10% of the class. What is the minimum score needed to get an A?

(d) Between what two values are the middle 68% of the scores? (Enter the smaller number in the first box.)

Solve using R.
You will need library(resampledata) and the dataset FlightDelays. Conduct a hypothesis test to see whether there is a difference in the variances of flight delay length between the two airlines.
1) Set a hypothesis for this test using appropriate notation
2) Using R, find the value of the observed test statistic
3) Using R, compute the P-value of the observed test statistic using a permutation distribution with N=10^5-1 resamples.

If possible use comments so that it is easier to study.

Thanks A lot!!

Find the value of the probability of the standard normal variable Z corresponding to the shaded area under the standard normal curve. (Round your answer to four decimal places. You may need to use the appropriate table in the Appendix of Tables to answer this question.) P(0.2 < Z < 1.83) = ?

5. Construct a dotplot of the body temperatures. Which does a better job of illustrating the distribution of the data: the histogram from question 2 or the dot plot?

1. Suppose that beer industry representatives hypothesize that the marginal propensity to buy beer out of an additional dollar of income is $0.01. Conduct a hypothesis test to determine if there is any validity to their conjecture. Use a = 1%.  
2. Conduct a hypothesis test to determine if the regressors are jointly significant in explaining the quantity of beer purchased. Be sure to state the null and alternative hypotheses formally