6. Provide example of your own research question. Formulate hypothesis for your research question and independent and dependent variables for this question.

An environmentalist wants to find out the fraction of oil tankers that have spills each month.

Step 1 of 2:

Suppose a sample of 292 tankers is drawn. Of these ships, 58 had spills. Using the data, estimate the proportion of oil tankers that had spills. Enter your answer as a fraction or a decimal number rounded to three decimal places.

Step 2 of 2:

Suppose a sample of 292 tankers is drawn. Of these ships, 58 had spills. Using the data, construct the 80% confidence interval for the population proportion of oil tankers that have spills each month. Round your answers to three decimal places.

What type of data would be collected by the following survey questions? (a) How many pairs of shoes do you own? (b) What color are your eyes? (c) Which brand of soft drink do you prefer? (d) What is your SAT score? (e) Are you planning to vote this year?

A regression analysis of college faculty salaries included several predictors, including a dummy variable for gender (male = 1) and a dummy variable for race (nonwhite = 1). Assume gender takes on the values male and female, and race takes on the values nonwhite and white. For annual income measured in thousands of dollars, the estimated coefficients were 0.76 for gender and 0.62 for race. At particular settings of the other predictors, the estimated mean salary for white females was 30.2 thousand. Find the estimated means for the other three groups. What is the estimated mean for nonwhite males?

a packing plant fills bags with cement. the weight X kg of a bag can be modeled normal distribution with mean 50kg and standard deviation 2kg.

a) Find the probability that a randomly selected bag weighs more than 53 kg.

b)find the weight that exceed by 98% of the bags

c)3 bags are selected randomly. Find the probability that two weigh more than 53 kg and one weigh less than 53kg

In its Fuel Economy Guide for 2016 model vehicles, the Environmental Protection Agency provides data on 11701170 vehicles. There are a number of high outliers, mainly hybrid gas‑electric vehicles. If we ignore the vehicles identified as outliers, however, the combined city and highway gas mileage of the other 11461146 vehicles is approximately Normal with mean 23.023.0 miles per gallon (mpg) and standard deviation 4.94.9 mpg.

The quartiles of any distribution are the values with cumulative proportions 0.250.25 and 0.75.0.75. They span the middle half of the distribution.

What is the first quartile of the distribution of gas mileage? Use Table A and give your answer rounded to two decimal places.

?1=Q1=

mpg

What is the third quartile of the distribution of gas mileage? Use Table A and give your answer rounded to two decimal places.

?3=

how to interpret confidence intervals and how NOT to interpret them.

What are the assumptions to justify the use of hypothesis testing?

If the null hypothesis is rejected, what can we conclude? If we know that 60% of ASU students like the parking and 50% of the community as a whole likes the parking, and the difference between the sample and population are tested, with the null rejected, what do we conclude? Is the difference significant? Not significant? Are ASU students significantly more likely or less likely to like the parking? Are they equally likely?

In order to reject the null when using a t distribution with small samples, what is needed? Consider size of the test statistic. Why?

I dont know what to do: Is there a significant difference between drug type and mean relative-change* of Cholesterol from screening to follow up?

* Relative Change = (Follow up - Initial) / Initial

Why is it crucial to know the level of measurement (nominal, ordinal, metric) when conducting significance testing? What flaw is evident with SPSS in this regard?

A researcher wants to conduct a before/after study on 12 subjects to determine if a treatment results in any difference in scores. Scores are obtained on the subjects both before and after the treatment. After subtracting the after scores from the before scores, the average difference is computed to be 3.40 with a sample standard deviation of 1.21. Assume that the differences are normally distributed in the population. If the researcher wanted to construct a 98% confidence interval for the difference between the (after - before) means, the t value to be used in the computations will be

A) 2.3027

B) 2.3281

C) 2.6810

D) 2.7181

A recent study reported that 51​% of the children in a particular community were overweight or obese. Suppose a random sample of 500 public school children is taken from this community. Assume the sample was taken in such a way that the conditions for using the Central Limit Theorem are met. We are interested in finding the probability that the proportion of​ overweight/obese children in the sample will be greater than 0.47. Complete parts​ (a) and​ (b) below. . Calculate the probability that 47​% or more of the sample are overweight or obese.

A statistician calculates that 7% of Americans own a Rolls Royce. If the statistician is right, what is the probability that the proportion of Rolls Royce owners in a sample of 613 Americans would differ from the population proportion by greater than 3% ? Round your answer to four decimal places.

A mathematics achievement test is given to students prior to entering a certain college. A sample of 10 students was selected and their progress in calculus observed:

e) Complete the ANOVA table for the least squares estimate for the regression line.

f)  Test at the 5% significance level whether the model is useful for predicting the final calculus grade.

g)  Give a 95% confidence interval for the mean final calculus grade when the achievement test score is 50.

h) Give a 95% prediction interval for the final calculus grade when the achievement test score is 50. Is the interval wider or narrower than the confidence interval? Why?

The reading speed of second grade students in a large city is approximately​ normal, with a mean of 89 words per minute​ (wpm) and a standard deviation of 10 wpm. A teacher instituted a new reading program at school.

After 10 weeks in the​ program, it was found that the mean reading speed of a random sample of 22 second grade students was 91.2 wpm. What might you conclude based on this​ result?

Select the correct choice below and fill in the answer boxes within your choice. ​(Type integers or decimals rounded to four decimal places as​ needed.)

A. A mean reading rate of 91.2 wpm is not unusual since the probability of obtaining a result of 91.2 wpm or more is ____. This means that we would expect a mean reading rate of 91.2 or higher from a population whose mean reading rate is 89 in _____ of every 100 random samples of size n=22 students. The new program is not abundantly more effective than the old program.

B. A mean reading rate of 91.2 wpm is unusual since the probability of obtaining a result of 91.2 wpm or more is ______. This means that we would expect a mean reading rate of 91.2 or higher from a population whose mean reading rate is 89 in _____ of every 100 random samples of size n=22 students. The new program is abundantly more effective than the old program.