The following table reports the fasting glucose levels of a sample of potential participants in a research study investigating the efficacy of a new insulin-type drug.

A) Calculate the mean, median, mode, and standard deviation for the group.
B) Are there any potential outliers that may be affecting the statistics calculated in part A?

A medical researcher says that less than 24​%of adults in a certain country are smokers. In a random sample of 250 adults from that​ country,18.8​% say that they are smokers. At

alphaαequals=0.05, is there enough evidence to support the​ researcher's claim? Complete parts​ (a) through​ (e) below.​(a) Identify the claim and stateUpperH0and Upper H Subscript aHa.

What is the​ claim?

A.Less than 24​%of all adults are smokers.

B.Exactly 18.8​%of all adults are smokers.

C.Exactly 18.8​% of adults in the country are smokers.

D.Less than 24​%of adults in the country are smokers.Identify

Upper H0 and Upper H Subscript aHa.Upper H0​:

less than<greater than or equals≥greater than>less than or equals≤nothing

Upper H Subscript aHa​:

greater than>less than or equals≤not equals≠less than<greater than or equals≥nothing

​(Type integers or​ decimals.)

​(b) Find the critical​ value(s) and identify the rejection​ region(s).

The critical​ value(s) is/arez 0z0equals=nothing.

​(Round to three decimal places as needed. Use a comma to separate answers as​ needed.)

What​ is/are the rejection​ region(s)? Select the correct choice below and fill in the answer​ box(es) to complete your choice.

​(Round to three decimal places as​ needed.)A.zless than<nothingandzgreater than>nothing

B.zless than<nothing

C.zgreater than>nothing

​(c) Find the standardized test statistic z.zequals=nothing (Round to two decimal places as​ needed.)

​(d) Decide whether to reject or fail to reject the null hypothesis and​ (e) interpret the decision in the context of the original claim.

Reject or Fail to reject Upper H 0H0.

There is not or is enough evidence at the 55​%level of significance to support or reject the​ researcher's claim that less than 24% or exactly 18.8% of all adults or adults in the country are smokers.

1/12/2018 Section 9.1 Homework-Rachel Yehnert

2. Since an instant replay system for tennis was introduced at a major tournament, men challenged 1391 referee calls, with the result that 423 of the calls were overturned. Women challenged 765 referee calls, and 227 of the calls were overturned. Use a 0.01 significance level to test the claim that men and women have equal success in challenging calls. Complete parts (a) through (c) below.

a. Test the claim using a hypothesis test.

Consider the first sample to be the sample of male tennis players who challenged referee calls and the second sample to be the sample of female tennis players who challenged referee calls. What are the null and alternative hypotheses for the hypothesis test?

A. H0:p1≥p2 H1: p1 ≠p2 D. H0:p1=p2 H1: p1 >p2

Identify the test statistic.

B. H0:p1=p2 H1: p1 <p2 E. H0:p1≤p2 H1: p1 ≠p2

C. H0 : p1 = p2 H1: p1 ≠p2 F. H0:p1≠p2 H1: p1 =p2

z= 0.36
(Round to two decimal places as needed.)

Identify the P­value.

P­value = 0.721
(Round to three decimal places as needed.)

What is the conclusion based on the hypothesis test?

The P­value is greater than the significance level of = 0.01, so
is not sufficient evidence to warrant rejection of the claim that women and men have equal success in challenging calls.

b. Test the claim by constructing an appropriate confidence interval.
The 99% confidence interval is − 0.046 < p1 − p2 < 0.060 .

(Round to three decimal places as needed.)
What is the conclusion based on the confidence interval?

Because the confidence interval limits include 0, there does not appear to be a significant difference between the

two proportions. There is not sufficient evidence to warrant rejection of the claim that men and women have equal success in challenging calls.

c. Based on the results, does it appear that men and women have equal success in challenging calls?

It does not appear that men and women have equal success in challenging calls. Women have more

success.

It appears that men and women have equal success in challenging calls.

It does not appear that men and women have equal success in challenging calls. Men have more success.

The results are inconclusive.

How do you find each answer and how do you input it into stat crunch to get the answer

In a normal distribution curve, what percentage of the area under the curve is contained in the region, on one side of the mean, between 1 standard deviation from the mean and 2 standard deviations from the mean?

• A. 95%
• B. 68.27%
• C. 50%
• D. 27.24%%
• E. 13.59%

The tensile strength, X, of a tungsten component is normally distributed with a mean of 546 grams per square centimeter (gscm) and a standard deviation of 50 gscm.

e) What is the 97.1st percentile of tensile strength of our tungsten component in gscm?

f) Suppose we make 3 independent strength measurements of tungsten components. What is the probability that all 3 measurements are at least 500?

g) What is the probability that X is greater than 525 given that X is greater than 500?

h) Suppose X1,X2,,Xk are k independent strength measurements of tungsten components. Let Xbar be the mean of those k values. How large must k be so the variance of the distribution of Xbar equals .8?

3) The following observations are given for two variables.

Y: 5,8,18,20,22,30,10,7

X:2,12,3,6,11,19,18,9

Compute and interpret the sample covariance for the above data.

Compute the standard deviation for x.

Compute the standard deviation for y.

Compute and interpret the sample correlation coefficient.

Let X1, X2, X3 be independent having N(0,1). Let Y1=(X1-X2)/√2, Y2=(X1+X2-2*X3)/√6, Y3=(X1+X2+X3)/√3. Find the joint pdf of Y1, Y2, Y3, and the marginal pdfs.

1) null hypothesis

2) alternative hypothesis

3) where the region of rejection lies (upper tail, lower tail, both tails)

4) the test that is to be used

5) the degrees of freedom

6) the critical value of the test statistic

7) the computed value of the test statistic

8) the statistical decision (whether the null hypothesis is rejected or not)

9) the p-value

10) the assumptions you made in your work

Now, finally - Here is the question:

Trail mix is sold in individual pouches labeled as containing 8 ounces by weight. The weights of 40 pouches are measured (using a tared scale so that only the weight of the trail mix is measured). The sample mean is found to be 8.5 ounces. The sample standard deviation is calculated to be 0.4 ounces. At 95% confidence, is there evidence that the mean weight per pouch is different from 8 ounces?

A research center project involved a survey of 843 internet users. It provided a variety of statistics on internet users.

(a) The sample survey showed that 90% of respondents said the internet has been a good thing for them personally. Develop a 95% confidence interval for the proportion of respondents who say the internet has been a good thing for them personally. (Round your answers to four decimal places.)

(b) The sample survey showed that 71% of internet users said the internet has generally strengthened their relationship with family and friends. Develop a 95% confidence interval for the proportion of respondents who say the internet has strengthened their relationship with family and friends. (Round your answers to four decimal places.)

(c) Fifty-seven percent of internet users have seen an online group come together to help a person or community solve a problem, whereas only 25% have left an online group because of unpleasant interaction. Develop a 95% confidence interval for the proportion of internet users who say online groups have helped solve a problem. (Round your answers to four decimal places.)

Please respond with at least 175 words. What are a one tail and a two tailed test. Why are they important and what are their differences?

At a confidence level of 95% a confidence interval for a population proportion is determined to be 0.65 to 0.75. If the sample size had been larger and the estimate of the population proportion the same, this 95% confidence interval estimate as compared to the first interval estimate would be

Do bonds reduce the overall risk of an investment portfolio? Let x be a random variable representing annual percent return for Vanguard Total Stock Index (all stocks). Let y be a random variable representing annual return for Vanguard Balanced Index (60% stock and 40% bond). For the past several years, we have the following data.

(a) Compute Σx, Σx²,  Σy, Σy².

(b) Use the results of part (a) to compute the sample mean, variance, and standard deviation for x and for y. (Round your answers to two decimal places.)

(c) Compute a 75% Chebyshev interval around the mean for x values and also for y values. (Round your answers to two decimal places.)

Use the intervals to compare the two funds.

75% of the returns for the balanced fund fall within a narrower range than those of the stock fund.75% of the returns for the stock fund fall within a narrower range than those of the balanced fund.     25% of the returns for the balanced fund fall within a narrower range than those of the stock fund.25% of the returns for the stock fund fall within a wider range than those of the balanced fund.

(d) Compute the coefficient of variation for each fund. (Round your answers to the nearest whole number.)

Use the coefficients of variation to compare the two funds.

For each unit of return, the stock fund has lower risk.For each unit of return, the balanced fund has lower risk.     For each unit of return, the funds have equal risk.

If s represents risks and x represents expected return, then s/x can be thought of as a measure of risk per unit of expected return. In this case, why is a smaller CV better? Explain.

A smaller CV is better because it indicates a higher risk per unit of expected return.A smaller CV is better because it indicates a lower risk per unit of expected return.     

Using the data in RDCHEM.RAW, the following equation was obtained by OLS:
\ rdintens = 2.613 + .00030sales + .0000000070sales2
(.429) (.00014) (.0000000037)
n = 32, R2 = .1484
i) At what point does the marginal effect of sales on rdintens become negative?
ii) Would you keep the quadratic term in the model? Explain.
1
iii) Define salesbil as sales measured in billions of dollars: salesbil = sales 1,000. Rewrite the estimated equation with salesbil and salesbil2 as the independent variables. Be sure to report standard errors and the R-squared. [Hint: Note that salesbil2 = sales2 (1,000)2 .]
iv) For the purpose of reporting the results, which equation do you prefer?

Given the statistics below, what is the appropriate analysis, the test statistic, and the associated effect size?

Sample size: 60.
Sample mean: 1080.
Sample standard deviation: 60.
Population mean: 1000.