Q: Calculate the mean, standard deviation, and 95% confidence limits for each set.

Q2: A type of steel contains 1.12% nickel and the standard deviation is 0.03%. The following data are collected (in percent)

a) 1.10 b) 1.08 c) 1.09 d) 1.12 e) 1.09

Is there an indication of bias in the method at the 95% level?

Why are measures of relative standing (e.g.. percentiles, percentile ranks, and standard scores) important?

The following data were drawn from a normal population. Find a 98.4% confidence interval for the mean.

7 21 20 8 14 12 18 14 9 23

1. Many years ago, Detroit had a six-month newspaper strike that closed down all its newspapers. During the strike, Detroit’s suicide rate fell very sharply (that is, there were far fewer suicides), but returned to its usual rate when the papers resumed publishing. Do the following: (a) Make up a theoretical model that would account for this observation and (b) generate a total of two interesting hypotheses from the model that could potentially be tested.

Using traditional methods it takes 105.0 hours to receive a basic driving license. A new license training method using Computer Aided Instruction (CAI) has been proposed. A researcher used the technique on 290 students and observed that they had a mean of 106.0 hours. Assume the standard deviation is known to be 7.0 . Is there evidence at the 0.02 level that the technique performs differently than the traditional method? Step 4 of 5: Enter the decision rule. Step 5 of 5: Enter the conclusion.

Find the value of z such that 0.9108 of the area lies between −z − z and z. Round your answer to two decimal places.

An automobile manufacturer claims that its cars average more than 410 miles per tankful (mpt).
As evidence, they cite an experiment in which 17 cars were driven for one tankful each and
averaged 420 mpt. Assume σ = 14 is known.

a. Is the claim valid? Test at the 5 percent level of significance.

b. How high could they have claimed the mpt to be? That is, based on this experiment, what is the maximum value for µ which would have been rejected as an hypothesized value?

c. What is the power of the test in part (a) when the true value of µ is 420 mpt? (Hint: Your rejection region for part (a) was stated in terms of comparing Zobs with a cut-off point on the Z distribution. Find the corresponding x̅cut-off and restate your rejection region in
terms of comparing the observed x̅value with the x̅cut-off. Then assume H1 is true (i.e. µ
= 420 mpt) and find the probability that x̅is in the rejection region.)

Data: 7,-5, -8, 7, 9, 15, 0, 2, 13, 8, 6, -2, 4 (a) Mean= Mode= median= (b) Variance= Standard deviation= (c) Range= IQR(Interquartilerange)= (d) Mid-Range= Mid-Hinge=

1. A researcher has obtained the number of hours worked per week during the semester for a sample of 10 students:

21, 33, 26, 16, 32, 20, 29, 20, 19, 20

Use the data set to compute the mean, the median, the mode, the range, the sample variance, the sample standard deviation, the 10th percentile, The sum of the squared deviations of each value of X from the mean. Briefly explain what information about the variable is provided by your answers for the mean, median, mode, and standard deviation.

Scroll the bottom arrows to see the whole table. if I make it any smaller you will not be able to see the numbers clearly: Is there a relationship between the relative-change* in weight and the relative-change* in Cholesterol level from screening to follow up for patients taking Drug A?

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

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