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Student's t-Test

Hypothesis testing: t-statistic and z-statistic.

2.The A.C. Nelson Company Collects Data on the TV viewing habits of Americans and publishes the information in the Nielson report on television. 20 married couples are randomly selected. Their weekly viewing times, in hours are as follows Husband: 21,56,34,30,41,35,26,38,27,30,31,30,32,15,36,20,43,4,16,21 Wife: 24,55,55,34

Hypothesis testing, z-scores, chi square, t-tests, and confidence intervals.

1. Find the Z -score and percentiles for the following calculations. Interpret your findings: a) Distribution of scores: Mean= 80 Standard Deviation=5 Scores are: X= 68, 75, 64 and 54 b) A researcher is testing a null hypothesis at the 0.05 level, would you accept or reject the null hypothesis? Z= -2.30 Z= 0.

Mean Times

For one of the tasks in a manufacturing process, the mean time for tasks completion has historically been 35.0 minutes, with a standard deviation of 2.5 minutes. Workers have recently complained that the machinery used in the task in wearing out and slowing down. In response to the complaints, plant engineers have measured the

One sample t test for mean..

An outbreak of food-borne sickness was attributed to Salmonella enteritidis. It determined that the source of the illness was spinach. Nine production runs are sampled from the spinach processing company the spinach to determine the level of Salmonella enteritidis. Levels in MPN/g are as follows: .793 .519 .392 .419 .5

One sample t test....

A. Based on this data can the college conclude that the students in the new program performed better than the rest of the class> A one-tailed test is used equalling .05 b. Can the college conclude that the students in the new program are significantly different from the rest of the freshman class? A two-tailed test is used

Hypothesis Testing: Weight Loss

The following table shows the results after four weeks (number of pounds lost). Drug Placebo 9 8 5 6 11 2 8 3 6 5 3 6 14 2 You want to prove that the drug is effective with α=.05. Calculate the following 1) Mean and standard deviation for each sample. 2) Since i

Important information about One sample t test

An industrial plant wants to determine which of two types of fuel, electric or gas, is more cost efficient (measured in cost per unit of energy). Independent random samples were taken of plants using electricity and plants using gas. These samples consisted of 14 plants using electricity, which had a mean cost per unit of $49.

The solution to Hypothesis test : t test

The International Council of Shopping Centers reports that the average teenager spends $39 during a shopping trip to the mall. The promotions director of a local mall has used a variety of strategies to attract area teens to his mall, including live bands and "teen-appreciation days" that feature special bargains for this age gr

Perform a left tailed t-test

In this exercise, assume that a simple random sample has been selected from a normally distributed population. Find the null and alternative hypotheses, test statistic, P-value (or range of P-values), critical value(s), and state the final conclusion. Claim: The mean life span of desktop PCs is less than 7 years.

Test for differences between the means

Dr. Justin Case wants to explore whether or not students perform better if they cram for a test (massed practice) or if they space their studying over weeks (distributed practice). The massed practice group studies for 8 hours the night before a quiz; the distributed practice group also studies for 8 hours, but does it in 2-hour

Hypothesis testing

Please see attached 42. The president of the American Insurance Institute wants to compare the yearly costs of auto insurance offered by two leading companies. He selects a sample of 15 families, some with only a single insured driver, others with several teenage drivers, and pays each family a stipend to contact the two c

5-Step Hypothesis Testing

Please see attachment Perform a 5 step hypothesis of number of males and females 25 to 29 years of age with bachelor degrees. 1% tcrit. ( percentage expressed using decimals ) Year Subjects Males Females 2003 1 .50 .53 200

Independent government agency

An independent government agency is interested in comparing the heating is interested in comparing the heating cost of all-electric home and those of home heated with natural gas.  A sample of eight all-electric homes is matched with eight homes of similar size and other features that use natural gas.  The heating costs for Ja

Probability - Independent - Related-Samples t-test

Bring to mind a real-world situation or problem that could be addressed using an independent- or related-samples t test. However, the real-world situation or problem selected to address, the independent and dependent variables you would study, an explanation of whether an independent-samples or related-samples t test is most ap

Hypothesis Testing

An Ohio university wishes to demonstrate that car ownership is detrimental to academic achievement. A random sample of 100 students who do not own cars had a mean GPA of 2.68 with a standard deviation of 0.6, while the same size of sample who own cars had a mean GPA of 2.55 with a standard deviation of 0.7. Can the university

Independent sample t test population

Please see the attached file. Problem 8-55 Two movies were screen-tested at two different samples of theaters. Mystic river was viewed at 80 theaters and was considered a success in terms of box office sales in 60 of these theaters. Swimming Pool was viewed at a random sample of 100 theaters and was considered a success

The solution to One sample t test

Fishing Trout. Pyramid Lake is on the Paiute Indian Reservation in the Nevada. The lake is famous for cutthroat trout. Suppose a friend tells you that the average length of trout caught in Pyramid lake is = 19 inches. However the creel survey reported that for a random sample of 51 fish caught, the mean length was xbar = 18.5

Independent sample t test..

The average mpg usage for a 2004 Ford Expedition 2WD for a sample of 10 tanks of gas was 17.0 with the standard deviation of 0.8. For a Ford Explorer 2WD, the average mpg usage for a sample of 10 tanks of gas was 18.5 with a standard deviation of 1.0. (a) Assuming equal variances, at a (alpha) = .01. is the true mean mpg lower

Paired T test for blood pressure data

D. The Sunbeam Corporation makes a wide variety of appliances for the home. One product is a digital blood pressure gauge. For obvious reasons, the blood pressure readings made by the monitor need to be accurate. When a new model is being designed, one of the steps is to test it. To do this, a sample of people is selected.

Color-Distance Illusion Analysis

Having trouble entering data it is ok to use excel. SPSS t-Tests (Independent Samples and Paired Samples) Scenario: The color-distance illusion (Kantowitz, Roediger, & Elmes, 1997) suggests that in art, warm colors (yellow, orange, red, and blends of these colors) appear to move toward the viewer when viewed from a

Hypothesis testing for the mean of nail length.

The mean age of 25 randomly selected college seniors was found to be 23.5 years, and the standard deviation of all college seniors was 1.3 years. Which of the following is the correct symbol for 1.3 years? A. m B. s C. s D. A machine produces 3-inch nails. A sample of 10 nails was selected and the lengths determine

Distribution Types, Mean, and Sample Analysis

1) In what ways is the t distribution similar to the standard normal distribution? In what ways is the t distribution different from the standard normal distribution? How does the formula for the t test differ from the formula for the z test? 2) Choose a variable. Before collecting the data, decide what a likely average migh

Testing of hypothesis problem: Independent t-test

A sample of 25 concession stand purchases show a mean purchase of $5.29 with a standard deviation of $3.02. However, a later showing of the same movie, a sample of 25 purchases where the mean was $5.12 with a standard deviation of $2.14. The means appear to be very close, but not the variances. At alpha = .05, is there a dif

Calculating degrees of freedom, t-tests and critical values

Suppose that a one-tailed t-test is being applied to find out if the population mean is less than $212. The level of significance selected is 0.01 and 26 accounts are sampled. What is the critical value? A machine is set to fill the small size packages of M&M candies with 56 candies per bag. A sample revealed: 3 bags of 5