Few Statistics Questions

The chi-square goodness-of-fit test can be used to test for:

A company operates four machines during three shifts each day. From production records, the data in the table below were collected. At the .05 level of significance test to determine if the number of breakdowns is independent of the shift.

The standard error of the estimate, s_est, is essentially the

A linear regression analysis produces the equation

y = 5.32 + (-0.846)x

Which of the following statements must be true?

In regression analysis, the variable we are trying to explain or predict is called the

Multiple myeloma or blood plasma cancer is characterized by increased blood vessel formulation in the bone marrow that is a prognostic factor in survival. One treatment approach used for multiple myeloma is stem cell transplantation with the patient’s own stem cells. The following data represent the bone marrow microvessel density for a sample of 7 patients who had a complete response to a stem cell transplant as measured by blood and urine tests. Two measurements were taken: the first immediately prior to the stem cell transplant, and the second at the time of the complete response.

A field researcher is gathering data on the trunk diameters of mature pine and spruce trees in a certain area. The following are the results of his random sampling. Can he conclude, at the .10 level of significance, that the average trunk diameter of a pine tree is greater than the average diameter of a spruce tree?

Suppose that the mean time for a certain car to go from 0 to 60 miles per hour was 7.7 seconds. Suppose that you want to test the claim that the average time to accelerate from 0 to 60 miles per hour is longer than 7.7 seconds. What would you use for the alternative hypothesis?

A severe storm has an average peak wave height of 16.4 feet for waves hitting the shore. Suppose that a storm is in progress with a severe storm class rating. Let us say that we want to set up a statistical test to see if the wave action (i.e., height) is dying down or getting worse. If you wanted to test the hypothesis that the waves are dying down, what would you use for the alternate hypothesis? Is the P-value area on the left, right, or on both sides of the mean?

The “Pizza Hot” manager commits a Type I error if he/she is

        In order to be accepted into a top university, applicants must score within the top 5% on the SAT exam. Given that SAT test scores are normally distributed with a mean of 1000 and a standard deviation of 200, what is the lowest possible score a student needs to qualify for acceptance into the university?

The upper limit of the 90% confidence interval for the population proportion p, given that n = 100; and    = 0.20 is

In a normal distribution, changing the standard deviation:

The binomial distribution can occur in which of the following situations?

I. whenever we are interested in the number of events that occur over a given interval of time
II. whenever we sample from a population with only two types of members
III. whenever we perform a sequence of identical experiments, each of which has only two possible outcomes

If A and B are any two events with P(A) = .8 and then is:

A sport preference poll yielded the following data for men and women. Use a 5% significance level and test to determine if sport preference and gender are independent.

What is the test value for this hypothesis test?

Answer:   [removed] Round your answer to two decimal places.

What is the critical value for this hypothesis test? 

Answer:  [removed]  Round your answer to two decimal places.

What is the conclusion for this hypothesis test?  Choose one.

1.  There is sufficient evidence to support the claim that one’s sport preference is dependent on one’s gender.
2. There is not sufficient evidence to support the claim that one’s sport preference is dependent on one’s gender.

Answer:  [removed]  Enter only a 1 or 2 for your answer.

The marketing manager of a large supermarket chain would like to determine the effect of shelf space (in feet) on the weekly sales of international food (in hundreds of dollars). A random sample of 12 equal –sized stores is selected, with the following results:

Using the equation of the regression line for these data, predict the average weekly sales (in hundreds of dollars) of international food for stores with 13 feet of shelf space for international food.

Place your answer, rounded to 3 decimal places , in the blank.  Do not use a dollar sign.  For example, 2.345 would be a legitimate entry.  [removed]

An investor wants to compare the risks associated with two different stocks. One way to measure the risk of a given stock is to measure the variation in the stock’s daily price changes.

In an effort to test the claim that the variance in the daily stock price changes for stock 1 is different from the variance in the daily stock price changes for stock 2, the investor obtains a random sample of 21 daily price changes for stock 1 and 21 daily price changes for stock 2.

The summary statistics associated with these samples are: n₁ = 21, s₁ = .849, n₂ = 21, s₂ = .529.  

If you follow Bluman’s advice and place the larger variance in the numerator, what is the test value associated with this test of hypothesis?  Place your answer, rounded to 3 decimal places, in the blank.  For example, 3.456 would be a legitimate entry.  [removed] 

The length of time to complete a door assembly on an automobile factory assembly line is normally distributed with mean 6.7 minutes and standard deviation 2.2 minutes. For a door selected at random, what is the probability the assembly line time will be between 5 and 10 minutes? Place your answer, rounded to 4 decimal places, in the blank. For example, 0.1776 would be a legitimate answer.  [removed]

Senior management of a consulting services firm is concerned about a growing decline in the firm’s weekly number of billable hours. The firm expects each professional employee to spend at least 40 hours per week on work. In an effort to understand this problem better, management would like to estimate the standard deviation of the number of hours their employees spend on work-related activities in a typical week. Rather than reviewing the records of all the firm’s full-time employees, the management randomly selected a sample of size 51 from the available frame. The sample mean and sample standard deviations were 48.5 and 7.5 hours, respectively.

Construct a 90% confidence interval for the standard deviation of the number of hours this firm’s employees spend on work-related activities in a typical week.

Place your LOWER limit, in hours, rounded to 1 decimal place, in the first blank. For example, 6.7 would be a legitimate entry. [removed]

Place your UPPER limit, in hours, rounded to 1 decimal place, in the second blank. For example, 12.3 would be a legitimate entry. [removed]

In a survey, 55% of the voters support a particular referendum. If 40 voters are chosen at random, and X is the number of voters that support this referendum, find the mean and variance of X. Place the mean in the first blank [removed]and place the variance in the second blank. [removed]

At a university, the average cost of books per student has been $600 per student per semester. The Dean of Students believes that the costs are increasing and that the average is now greater than $600.  He surveys a sample of 40 students and finds that for the most recent semester their average cost was $645 with a standard deviation of $75.  What is the test value for this hypothesis test?

Test value: [removed]Round your answer to two decimal places as necessary.

A probability experiment has two steps. There are two possible results for the first step, call them “A” and “B”. If the result for the first step was “A”, then there would be 4 possible results for the second step. If the result for the first step was “B”, then there would be 16 possible results for the second step. How many possible outcomes are there for this experiment? Place your answer in the blank. Do not use any decimal point or comma. For example, 45 would be a legitimate entry.