2) An investor wants to assess at confidence level of 98% if a medicament can improve the marks of students. He notices that for the following daily dozes: 2,2.5,3,4.5,7 mg, the improvement over the students that studied the same but took no mental boosters were of: 3,4,4.6,6, 8.5 percent. At a confidence interval of 99%, what results would you expect for the students who take a daily dose of 6.5 mg? show full calculations.

3) A T 95 tank weighs 75 tons. A businessman wants to buy a couple of thousand tanks for hunting expedition in Texas. He will buy only if the tanks are really as specified and refuse to buy them if they statistically they weigh less. He takes a sample of 8 tanks and finds their average weight at 74.7 tons with a standard deviation of 0.3 tons. He wants to use a significance level of 2%. What will be his best course of action. Show all the work and justify your answer.

4) A car has a gas mileage of 500 miles per gallon of gasoline, with a standard deviation of 10 miles per gallon. What would be the gas mileage of the top 40% of such cars? What would be the mileage range for 70% of the cars? What %of cars will have a mileage of 530 miles per gallon of less?

5) The probability that a student answers a multiple question correctly is 27%, in an exam with 6 questions. What would be the probability the students answers correctly at random: no question, all questions, 6 questions, less than two and more than 4 questions? Answer individually all these questions, show all the work and explain your logic.

6) Mr. G. just won the jackpot with one ticket. He chose correctly 6 numbers out of 52 numbers and 2 stars our out of 12 stars. What was his probability of winning when he bought the ticket? Show full work and explain your answer.

Solution Preview

1. Please refer to the excel attachment for the calculations.
2. Please refer to the excel attachment for the calculations.
3. Null Hypothesis: The mean weight is greater than or equal to 75 tons.
H0: u >= 75
Alternate Hypothesis: The mean weight is less than 75 tons.
H1: u < 75

Let us ...

Solution Summary

The expert finds the range, mode, median, mean, IQR, standard deviation and variance. The mental boosters are provided.

In a statistics lecture, students are asked whether or not they enjoyed doing statistics. Random sample of 50 students was taken and 30 of them said that they enjoyed doing statistics. The lecturer claimed that more than 50% of the students enjoyed doing statistics.
(i) Test, at the 5% level of significance, whether or not

From past experiences, Prof. A believes that the average score on final exam is 75. A sample of 20 students' exam scores is as follows: 80, 68, 72, 73, 76, 98, 71, 71, 35, 50, 63, 71, 70, 70, 76, 75, 69, 70, 72, 74
Assuming a normal population, can we conclude that the students' average is still 75? Use alpha = 0.01
a. I

Are Confidence intervals part of descriptive statistics or inferential statistics- why? Why would we use confidence intervals instead of point estimates? Give an example of the use of a confidence interval and why you would prefer it over point estimates in your example.

A survey of individuals who passed the BAR finds the average starting salary for lawyers to be $75,215 for 36 individuals sampled. If the population standard deviation is $15,990 find a 90% confidence interval for the true mean.
Round your answers to the nearest whole number.

How is the confidencelevel determined? Who in your workplace might set this level?
Should companies use the same confidence interval each time a confidence interval is determined or should the level change based on situations? If it changes based on situations, what type of situations might call for higher confidencelevels?

Directions:
1) Calculate a point estimate and a 95% confidence interval of the mean. Assuming your data set is normally distributed, determine an appropriate sample size if the maximum allowable error is three units for the attached data set. (Please note: the three units are measure in the unit of measurement of the attache

1. A bank located in a commercial district of a city has developed an improved process for serving customers during the noon to 1:00PM peak lunch period. The waiting time (as defined as the time the customer enter the line until he or she is served) of all customers during this hour is recorded over a period of 1 week. A random

W. Bowen and T. Finegan (1965) published a paper titled "Labor Force Participation and Unemployment." In that paper they estimated the following regression using a data set of 78 cities:
i = 94.2 - .24Ui + .2Ei -.69Ii - .06Si + .002Ci - .8Di
(.08) (.06) (.16) (.18) (.03) (.43)
The standard errors for the OLS coefficient