You are still trying to estimate the girth of Kerrville toads. You collect 100 toads from many different ponds, rivers, witches cauldrons, etc around Kerrville. This is in the data set data("toad_girth") in my package. Using this data set find a 95% confidence interval for the population standard deviation of the toad girths:

In a study of the accuracy of fast food​ drive-through orders, one restaurant had 32 orders that were not accurate among 398 orders observed. Use a 0.10 significance level to test the claim that the rate of inaccurate orders is equal to​ 10%. Does the accuracy rate appear to be​ acceptable?

Identify the null and alternative hypotheses for this test. Choose the correct answer below.

A. H0​: p≠0.1 H1​: p=0.1

B. H0​: p=0.1 H1​: p≠0.1

C. H0​: p=0.1 H1​: p<0.1

D. H0​: p=0.1 H1​: p>0.1

Identify the test statistic for this hypothesis test.

The test statistic for this hypothesis test is _____ (Round to two decimal places as​ needed.)

Identify the​ P-value for this hypothesis test.

The​ P-value for this hypothesis test is _____ ​(Round to three decimal places as​ needed.)

Identify the conclusion for this hypothesis test.

A. Reject H0. There is not sufficient evidence to warrant rejection of the claim that the rate of inaccurate orders is equal to​ 10%.

B. Fail to reject H0. There is sufficient evidence to warrant rejection of the claim that the rate of inaccurate orders is equal to​ 10%.

C. Reject H0. There is sufficient evidence to warrant rejection of the claim that the rate of inaccurate orders is equal to​ 10%.

D. Fail to reject H0. There is not sufficient evidence to warrant rejection of the claim that the rate of inaccurate orders is equal to​ 10%.

Does the accuracy rate appear to be​ acceptable?

A. Since there is sufficient evidence to disprove the theory that the rate of inaccurate orders is equal to​ 10%, the accuracy rate is acceptable.

B. Since there is not sufficient evidence to disprove the theory that the rate of inaccurate orders is equal to​ 10%, it is possible that the accuracy rate is acceptable.

C. Since there is sufficient evidence to disprove the theory that the rate of inaccurate orders is equal to​ 10%, the accuracy rate is not acceptable. The restaurant should work to lower that rate.

D. Since there is not sufficient evidence to disprove the theory that the rate of inaccurate orders is equal to​ 10%, the accuracy rate is not acceptable. The restaurant should work to lower that rate

Paired sample test, (1) construct a 95% confidence interval and (2) conduct a t-test (α = 5%). This is to report to the NFL commisioner regarding points scored vs points allowed.

Data sets below

The developers of a new online game have determined from preliminary testing that the scores of players on the first level of the game can be modelled satisfactorily by a Normal distribution with a mean of 185 points and a standard deviation of 28 points. They would like to vary the difficulty of the second level in this game, depending on the player’s score in the first level.

(a) The developers have decided to provide different versions of the second level for each of the following groups:

(i) those whose score on the first level is in the lowest 25% of scores

ii) those whose score on the first level is in the middle 50% of scores

(iii) those whose score on the first level is in the highest 25% of scores. Use the information given above to determine the cut-off scores for these groups. (You may round each of your answers to the nearest whole number.)

(b) In the second level of the game, the developers have also decided to give players an opportunity to qualify for a bonus round. Their stated aim is that players from group (i) should have 75% chance of qualifying for the bonus round, players from group (ii) should have 55% chance of qualifying for the bonus round and that players from group (iii) should have 30% chance of qualifying for this round. Let ?, ? and ? respectively denote the events that a player’s score on the first level was in the lowest 25% of scores, the middle 50% of scores and the highest 25% of scores, and let ? denote the event that the player qualifies for the bonus round. Use event notation to express the developers’ aim as a set of conditional probabilities.

(c) Based on the developers’ stated aim, find the total probability that a randomly chosen player will qualify for the bonus round.

(d) Given that a player has qualified for the bonus round, what is the probability that the player’s score on the first level was in the middle 50% of scores for that level?

(e) Given that a player has not qualified for the bonus round, what is the probability that the player’s score on the first level was in the lowest 25% of scores for that level?

Let X and Y be two independent random variables such that X + Y has the same density as X. What is Y?

A marketing researcher predicts that college students will be more likely to purchase tickets for... A marketing researcher predicts that college students will be more likely to purchase tickets for the next football home game if their team won (vs. lost) the last game. The researcher asked 6 WSU students their willingness to purchase tickets (1= not likely at all, 7=very likely) and 6 EWU students their willingness to purhcase tickets (1=not likely, 7=very likely) (WSU won the game in the 2018 season)

WSU: 7 6 5 7 2 4

EWU: 6 5 6 5 1 6

In answering the questions, make sure to write down the following 7 steps.

Step 1. Establish null and alternative hypotheses (as a sentance and formula)

Step 2: Calculate the degrees of freedom

Step 3: calculate the t-critical using critical t-table

Step 4: calculate the Sum of Squares deviation

Step 5: Calculate t-obtained

Step 6: Specify the critical value and the obtained value on a t-distribution curve.

A personnel specialist with a large accounting firm is interested in determining the effect of seniority on hourly wages for secretaries. She selects at random 10 secretaries and compares their years with the company (X) and hourly wages (Y).

• Calculate the regression slope and intercept (2 points).
• Predict the hourly wage of a secretary that has been with the company for four years (1 point).
• Find the coefficients of determination and nondetermination, and interpret both values (2 points).

A random sample of 200 books purchased at a local bookstore showed that 72 of the books were murder mysteries. Let p be the true proportion of books sold by this store that is murder mystery. Construct a confidence in terval with a 95% degree of confidence.Compute the following:

a.Point estimate

b.Critical value

c.Margin of error

d.Confidence interval

e.Interpretation(confidence statement).

What is your favorite color? A large survey of countries, including the United States, China, Russia, France, Turkey, Kenya, and others, indicated that most people prefer the color blue. In fact, about 24% of the population claim blue as their favorite color.† Suppose a random sample of n = 54 college students were surveyed and r = 11 of them said that blue is their favorite color. Does this information imply that the color preference of all college students is different (either way) from that of the general population? Use α = 0.05. (a) What is the level of significance? 0.05 Correct: Your answer is correct. State the null and alternate hypotheses. H0: p = 0.24; H1: p > 0.24 H0: p = 0.24; H1: p ≠ 0.24 H0: p ≠ 0.24; H1: p = 0.24 H0: p = 0.24; H1: p < 0.24 Correct: Your answer is correct. (b) What sampling distribution will you use? The Student's t, since np > 5 and nq > 5. The standard normal, since np < 5 and nq < 5. The Student's t, since np < 5 and nq < 5. The standard normal, since np > 5 and nq > 5. Correct: Your answer is correct. What is the value of the sample test statistic? (Round your answer to two decimal places.) -0.04 Incorrect: Your answer is incorrect. (c) Find the P-value of the test statistic. (Round your answer to four decimal places.) 0.24 Incorrect: Your answer is incorrect.

Researchers watched groups of dolphins off the coast of Ireland in 1998 to determine what activities the dolphins partake in at certain times of the day ("Activities of dolphin," 2013). The numbers in Table 3 represent the number of groups of dolphins that were partaking in an activity at certain times of days. Is there enough evidence to show that the activity and the time period are independent for dolphins? Why or Why not? Test at the 1% level.

In 2003 and 2017 a poll asked Democratic voters about their views on the FBI. In​ 2003, 42​% thought the FBI did a good or excellent job. In​ 2017, 64​% of Democratic voters felt this way. Assume these percentages are based on samples of 1200 Democratic voters.

1) Can we​ conclude, on the basis of these two percentages​ alone, that the proportion of Democratic voters who think the FBI is doing a good or excellent job has increased from 2003 to​ 2017? Why or why​ not?

Select one:

a. No. Although a lesser percentage is present in the​ sample, the population percentages could be the same or even reversed.

b. No. Since a greater percentage is present in the​ sample, we cannot conclude that a lesser percentage of Democratic voters who think the FBI is doing a good or excellent job is present in the population.

c. No. Although a lesser percentage is present in the​ sample, the population percentages could be the​ same, but could not be reversed.

d. Yes. Since a lesser percentage is present in the​ sample, a lesser percentage of Democratic voters who think the FBI is doing a good or excellent job is present in the population.

2) Construct a 95​% confidence interval for the difference in the proportions of Democratic voters who believe the FBI is doing a good or excellent​ job, p1−p2. Let p1 be the proportion of Democratic voters who felt this way in 2003 and p2 be the proportion of Democratic voters who felt this way in 2017.

Select one:

a. (0.39, 0.45)

b. (-0.259, -0.181)

c. (-0.24, -0.20)

d. (0.63, 0.65)

The mean operating cost of a 737 airplane is $2071 per day. Suppose you take a sample of 49 of these 737 airplanes and find a mean operating cost of $2050 with a sample standard deviation of $106.

A.) what is the probability that a 737 will have an operating cost that is greater than the sample mean you have found? (show work)

B.) what is the probability that a plane would have an operating cost that is between $2050 and 2088.60 per day? (show work)

An educational psychologist wants to know if length of time and type of training affect learning simple fractions. Fifth graders were randomly selected and assigned to different times (from 1 to 3 hours) and different teaching conditions (old method vs. meaningful method). All students were then tested on the "fractions" subtest of a standard arithmetic test. What can the psychologist conclude with α = 0.01?

a) What is the appropriate test statistic?
---Select--- na one-way ANOVA within-subjects ANOVA two-way ANOVA

b) Compute the appropriate test statistic(s) to make a decision about H₀.
Train: p-value =  ; Decision:  ---Select--- Reject H0 Fail to reject H0
Time: p-value =  ; Decision:  ---Select--- Reject H0 Fail to reject H0
Interaction: p-value =  ; Decision:

A simple random sample of 60 items resulted in a sample mean of 75. The population standard deviation is 17.

Compute the 95% confidence interval for the population mean (to 1 decimal).

Assume that the same sample mean was obtained from a sample of 120 items. Provide a 95% confidence interval for the population mean (to 2 decimals).

What is the effect of a larger sample size on the margin of error?

Consider a game of chance consisting of a single trial with exactly two outcomes, which from a players perspective we will call "win" and "lose." To play the game, a player must wager an amount, which we will denote by a. If the player loses the game, a player loses their wager. If the player wins the game, then they keep their wager and they win $1.00. Denote the probability by p, where 0 < p < 1. Let the random variable X denote the amount won by the player.

A) Find the sample space of the random variable X.

B) Find the pmf of the distribution of the random variable X.

C) Compute the expression for E(X), the expected value of X.

D) A game is said to be fair if the expected amount won is 0. For what value of a, the amount wagered, would the game be described as a fair game?

E) For what vaules of a is E(X) >0?

F) For what values of a is E(X) <0?

G) Suppose a person is only willing to play if their expected amount won is non negative. For what values of a would this person be willing to play, and what values of a would this person not be willing to play?