An accountant wishes to predict direct labor cost (v) on the basis of the batch size (x) of a product produced in a job shop. Data for 12 production runs are given in Table 14.5, along with the Excel output from fitting a least squares Page 592 regression line to the data. a By using the formulas illustrated in Example 14.2 and the data provided, verify that (within rounding) bo = 18.488 and bị = 10.146, as shown on the Excel output. b Interpret the meanings of bo and b1. Does the interpretation of bọ make practical sense? c Write the least squares prediction equation. d Use the least squares line to obtain (1) a point estimate of the mean direct labor cost for all batches of size 60 and (2) a point prediction of the direct labor cost for an individual batch of size 60.

Matilda was curious if sample interquartile range (IQR) was an unbiased estima- tor of population IQR. She placed ping pong balls numbered from 0 to 32 in a drum and mixed them well. Note that the IQR of the population is 16. She then took a random sample of 5 balls and calculated the IQR of the sample. She replaced the balls and repeated this process for a total of 50 trials. Her results are summarized in the dotplot below, where each dot represents the sample IQR from a sample of 5 balls. H|| 5 10 15 25 Sample IQR Based on these results, does sample IQR appear to be a biased or unbiased estimator of population IQR? Explain briefly. 20

A lecturer at WIN wanted to know if he can predict student’s quiz results by asking them to complete a simple survey. The result of the survey is found in the file: Assignment 2 sem22020 data set 1.Quiz ResultActual Mark (0-15) for quiz student attainedEQRQuiz score (0-15) expected to get before taking the quizStudy Hrs.Number of hours per week (on average) spent studying for StatisticsAgeAge (in years)BBTSatisfaction rating of Big Bang TheorySexM=1 F=0MBMB=1 for good math background, otherwise 0MCMC= 1 if math centre is used regularly, otherwise 0AuHSAuHS = 1 if student completed high school in Australia, otherwise 0LMLM=1 if student likes math, 0 otherwiseTask 1: Variable List(a) Using the variables listed in the table above, Describe each variable.(b) State for each variable whether it is qualitative or quantitative; if it is qualitative, state whether it is nominal or ordinal, and if it is quantitative, state whether it is discrete or continuous.Task 2: HistogramCreate a histogram…

A photoconductor film is manufactured at a nominal thickness of 25 mils. The product engineer wishes to increase the mean speed of the film and believes that this can be achieved by reducing the thickness of the film to 20 mils. Eight samples of each film thickness are manufactured in a pilot production process, and the film speed (in microjoules per square inch) is measured. For the 25-mil film, the sample data result is.x₁ = 1.15 and S₁ = 0.11, while for the 20-mil film, the data yield 2 = 1.06 and s2 = 0.09. Note that an increase in film speed would lower the value of the observation in microjoules per square inch. Do the data support the claim that reducing the film thickness increases the mean speed of the film? Use a = 0.10 and assume that the two population variances are equal and the underlying population of film speed is normally distributed. The appropriate decision for the test is to reject the null hypothesis True False

A researcher, by using a sample of 3,294 USA individuals observed in 1987 wants to estimate how wage is affected by gender and education. To this end, he estimates with OLS the following model (standard errors in round brackets below the corresponding coefficient): R2 w; = 4.829 + 1.142 male; +0.041 exper; (0.197) (0.114) 0.0330 (0.024) where the hourly wage (in 1980 US dollars), w, is regressed on a gender dummy, male, which takes value of 1 if the worker is male and 0 if female, and the variable exper, the working experience (in years). Using the results in the equation above and assuming that the 6 OLS assumptions (i.e., including homoskedasticity and normality of the errors) hold, if you test that the coefficients of male and experience are jointly equal to 0 against a bilateral alternative (the critical value at a = 5% is equal to 3): O (a) You cannot perform the test with the available information O (b) You would reject at 5% but not at 1% O (c) You would reject at both 5% and 1%…

Each year from 1974 to 1990 the Gallup Polling Organization asked how happy people were in their marriage. The percentage of people that said “very happy” was plotted over time. Use the summary statistics below to compute the least squares regression line to predict the percent of those that are “very happy” based on the year. a) y = 759.0 - 0.3502x b) y = 2098 - 11.79x c) y = -629.3 - 0.3502x d) y = 1866 - 1.790x

What is the chi square-crit for the alpha level of 0.5 when you have 4 column categories and 4 row categories (4x4 grid) in a chi square analysis?

The management of a supermarket wants to find if there is a relationship between the number of times a specific product is promoted on the intercom system in the store(x) and the number of units of that product sold (y). To experiment, the management selected a product and promoted it on the intercom system for 7 days, recording the number of times this product was promoted each day and the number of units sold. Summaries of a study conducted gave the following results:  ∑x=177, ∑y= 144, SSxx=809.4286, SSyy=261.7143, SSxy= 407.8571  a) Calculate the correlation coefficient (r) relating number of times this product was promoted each day and the number of units sold.  b) Find the regression line.

A researcher wishes To determine the relationship between the number of Cows(in thousands) in counties in southwestern Pennsylvania and the milk production ( in millions of pounds.) After computing the least squares regression line, it is determined that r^2=0.9972. Which of the following is the correct interpretation of this value? Answer Choices: A.) none of the other answers is a correct interpretation  B.) About 99.72% of the changes in the number of cows are explained by changes in milk production  C.) About 99.72% of the change in milk production are explained by changes in the number of cows.

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