Explore BrainMass

Explore BrainMass

    Hypothesis Testing

    BrainMass Solutions Available for Instant Download

    Hypothesis Testing of Standard Deviation

    A manufacturer uses a new production method to produce steel rods. A random sample of 17 steel rods resulted in lengths with a standard deviation of 21.1cm. At the 0.10 significance level, test the claim that the new production method has lengths with a SD different form 3.5cm which was the SD for the old method. Identify the n

    Test Statistic: Population Proportion

    A claim was made that the proportion of drowning deaths in children attributable to beaches is more than 0.25 and the sample statistics include n=615 drowning deaths of children with 30% attributable to beaches. What is the value of the test statistic z?

    Analyze mileage and vehicle weight vs miles per gallon data

    See attached file. Using Data set 'G', choose the dependent variable (the response variable to be 'explained') and the independent variable (the predictor or explanatory variable) as you judge appropriate. Use a spreadsheet or a statistical package (e.g., MegaStat or MINITAB) to obtain the bivariate regression and required gr

    Hypothesis-Null & Alternative,P-value for F-test;2-Way ANOVA

    See attached file. Hypothesis - Null & Alternative, p-value for F-test (ANOVA) - How to determine significance difference in means 1) An investor wants to know if a difference exists, at a significance level of 0.05, between home prices in three subdivisions. Independent samples of homes from each of the three subdivis

    Hypothesis Test

    The Rocky Mountain district sales manager of Rath Publishing, Inc., a college textbook publishing company, claims that the sales representatives make an average of 36 sales calls per week on professors. Several reps say that this estimate is too low. To investigate, a random sample of 32 sales representatives reveals that the me


    1) If the correlation coefficient r is equal to 0.57, find the coefficient of determination. a) 0.68 b) 0.75 c) 0.45 d) 0.32 2) The prediction interval around y' for a specific x is a) A confidence interval for the true mean value of the y values that correspond to that x b) The value of y used to calculate the slo

    One Sample Tests of Hypothesis: Prop bets at Mirage for Super Bowl Sunday

    According to news reports, Las Vegas betting parlors increased the number of proposition (prop) bets available to gamblers for this year's Super Bowl (Example: Which team will be the first to suspend a starting player for a team rules violation?). It is believed that the mean number of prop bets per typical gambler is normally

    Waiting line model - Queuing Theory

    Question 1 Produce trucks arrive at the weigh station at the California border at a rate of 3 per hour according to a Poisson distribution. Livestock trucks arrive at that same weigh station at a rate of 2 per hour according to a Poisson distribution. What is the probability that the number of livestock trucks arriving at the

    Hypothesis Testing of Population Proportion: Traditional Method

    By using the Traditional Method and Z test value, find the following: The researcher estimated that out of the 100 students at least 50% of the students would be exposed to movies and TV w/ crude humor at least 2-4 times per week. With a sample of 50 students the researcher found that 57% of the students were exposed to crude

    Compute T-Value Obtained from Table

    Exhibit 13-3 Below you are given a partial Excel output based on a sample of 25 observations. Coefficients Standard Error Intercept 145.321 48.682 x1 25.625 9.150 x2 â?'5.720 3.575 x3 0.823 0.183 Refer to Exhibit 13-3. The t value obtained from the table to test an in

    More variation in the processing time of the new machine

    A computer manufacturer is about to unveil a new, faster personal computer. The new machine clearly is faster, but initial tests indicate there is more variation in the processing time. The processing time depends on the particular program being run, the amount of input data, and the amount of output. A sample of 16 computer run

    Hypothesis Testing & Variance: AIU job satisfactions data

    See data file attached. Using AIU's survey responses from the AIU data set,complete the following requirements in the form of a report: 1. Perform a two-tailed hypothesis test on both the intrinsic and the extrinsic variable's data, using a .05 significance level. 2. Begin by creating a null and an alternate statement

    Hypothesis Testing of Mean:IQ scores of Statistics Professor

    Null and Alternative hypothesis. For the following claim, find the null and alternative hypotheses, test statistic, P-value, critical value, and draw a conclusion. Assume that a simple random sample has been selected from a normally distributed population. Answer parts a-e. Claim: The mean IQ score of statistics professors

    Test the Claim of Average Minutes to Complete a 1 Mile Run

    Studies have shown that humans complete a 1 mile run in an average of 12.2 minutes. There is a separate group of 30 who complete a 1 mile run with an average of 8.67 minutes with a standard deviation of 0.33 minutes. a- Using a 0.05 significance level, test the claim that the population mean is different than 12.2 minutes bas

    Hypothesis Testing of Population Proportion Significance

    Joseph has a career batting average of 0.314%. In 2000 he had 179 hits of 663 at-bats. At the 5% significant level, test the claim that there is a significant difference between 2000 batting percent and his career batting percent of 0.314.

    Hypothesis Testing: Independent Sample t Test..

    See the attached file for the data. Insurance adjusters are concerned about the high estimates they are receiving from Jocko's Garage. To see if the estimates are unreasonably high, each of 10 damaged cars was taken to Jocko's and to another garage and the estimates recorded. Here are the results: Test the null hypothesi

    Conducting a hypothesis test for a population mean

    Please help with the following problem. You have a sample size of 120 and the population standard deviation of 20. You are testing the null hypothesis of whether the population mean is 120 or not. A. What are the critical values for rejection when Type I error is 5%? B. If actual mean is 121, find the Type II error C.

    Pew Research Automobiles Driving

    8.14 Do you enjoy driving your car? The Pew Research Center recently polled n = 1048 U. S. drivers and found that 69% enjoyed driving their automobiles. (a) Construct a 95% confidence interval for the proportion of U. S. drivers who enjoy driving their automobiles. (b) In 1991, a Gallup Poll reported this percent to be 79%


    1. Different neighbourhoods may have different crime statistics. A sample of 10 days in Neighbourhood A revealed the following number of crimes per day: 15 12 16 17 15 14 16 10 12 14 A sample of 12 days in Neighbourhood B revealed the following number of crimes per day: 17 13 15 18 16 19 11 21 22 13 16 18 At a 5% l

    Testing blood lipid levels

    More on blood lipid levels. LDL is also known as ' bad' cholesterol. Suppose the researchers wanted to test the hypothesis that LDL levels are higher in sedentary males than in sedentary females. Describe appropriate null and alternative hypotheses and carry out the significance test using a = 0.05. Report the test statistic wit

    Sample of NHTSA Conducted Crash Tests of Child Booster Seats

    The NHTSA conducted crash tests of child booster seats for cars. Listed below are results from those tests, with the measurements given in hic (standard head injury condition units). The safety requirement is that the hic measurement should be less than 1000 hic. Use a 0.01 significance level to test the claim that the sample is

    Statistics: Does ad placement matter?

    Does ad placement matter? Corporate advertising tries to enhance the image of the corporation. A study compared two ads from two sources, the Wall Street Journal and the National Enquirer. Subjects were asked to pretend that their company was considering a major investment in Performax, the fictitious sportswear firm in the ads.

    Statistics: Analysis of food intake and weight gain

    Food intake and weight gain. If we increase our food intake, we generally gain weight. Nutrition scientists can calculate the amount of weight gain that would be associated with a given increase in calories. In one study, 16 nonobese adults, aged 25 to 36 years, were fed 1000 calories per day in excess of the calories needed to

    Average annual income of dentists in 2005 was $110,000.

    The Bureau of Labor Statistics reported that the average annual income of dentists in the year 2005 was $110,000. A sample of 81 dentists, which was taken in 2006, showed an average annual income of $115,000. Assume the standard deviation of the population of dentists in 2006 is $36,000. a). Suppose you want to test whether t

    Calculating Mean and Standard Deviation: New Jobs Example

    The Department of Economic and Community Development (DECD) reported that in 2008 that average number of new jobs created per county was 450. The department also provided that following information regarding a sample of five counties in 2009. Bradley 410 Rhea 450 Marion 407 Grundy 428 Sequatchie

    Statistics: Tessler Electric utility, sample of telephone response time

    Tessler Electric utility requires service operators to answer the telephone calls from customers in an average time of 0.1 minute or less. A sample of 30 actual operator times are drawn, and the results are given in the following table. In addition, operators are expected to determine customer needs and either respond to them

    7-11 Find the critical values

    See attached file for full problem. 7-11. Do one of the following, as appropriate. (a) find the critical value (b) find the critical value (c) State that neither the normal nor the t distribution applies. Confidence level 90%; n = 16; o is known; population appears to be very skewed. Find the critical values: a.

    Minimum sample size given margin of error

    7-8. Use the given margin of error, confidence level, and population standard deviation (o) to find the minimum sample size required to estimate an unknown population means (u) Margin of error: 0.5 inches, confidence level: 90%, o=2.7 inches A confidence level of 90% requires a minimum sample size of ______