BST322 Week 4 Discussion 2

A sports shop selects a random sample and records the sales of items made in China and thosemade in America. Country of origin n mean St.Deviation           China 50 22.5 9.75           America 33 33.15 11.6                             What is the SE Mean for the sales from China?

Module 5 Measures of Dispersion Name Course and Year Exercise 5.1 Determine the sample variance and standard deviation for the following data. CI F 10-14 5 15-19 20 20-24 35 25-29 25 30-34 15 Total 100

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The reliability of an estimator is assessed in terms of its _____. Select one: a. mean  b. ease of computation c. coefficient of variation d. variance

K The first statistics exam had a mean of 71 and a standard deviation of 15 points; the second had a mean of 82 and a standard deviation of 5 points. Anna scored a 84 on both tests. Megan scored 94 on the first exam and 74 on the second. They both totaled 168 points on the two exams, but Anna claims that her total is better. Explain. The total of Anna's z-scores is, which is greater than Megantotal of (Round to one decimal place as needed.)

2. Which of following statement is NOT correct about standard error? a. the square root of the estimated variance of coefficient is called standard error b. standard error is a measure of the relative precision of the estimate c. larger value indicate more uncertainty about the estimated coefficient d. none of above

For the following time series plots, explain what type of transformation, if any, would make the variance more stable.

Given the following data .Find the OLS estimators using the deviation method. Y 6 10 9 14 7 5   X1 1 3 2 -2 3 5   X2 3 -1 4 6 2 4

2) You work for the FTC. A manufacturer of detergent claims that the mean weight of detergent is at least 6.5 lb. You take a random sample of 64 containers. You calculate the sample average to be 6.43 lb. with a standard deviation of .14 lb. At the 0.02 level of significance, is the manufacturer correct?

Calculate SP (the sum of products of deviations) for the following scores, Note: Bothmeans are decimal values, so the computational formula works well.X Y0 41 10 54 12 11 3

Please no written by hand and no emage

The fitted values and residuals have the following properties: a. the sample of the average of the residuals is zero b. the sample covariance between each independent variable and the OLS residual is zero c. the sample covariance between the OLS fitted value and the OLS residual is zero d. All of the above is correct ○ a. a O b. b О с. с O d. d

no.4 only

What do you mean by Sample Variance, Sample Standard Deviation,and Standard Error?

The covariance by itself is not very useful because ___________.

2. Below is the estimated demand function for high-class tea (cups per month). Variable Estimated Coefficient Standard Error Constant  0.22 0.034 Price of high-class tea (in $100) -1.43 0.521 Income level (in $1000) 0.86 0.186 Being male 3.29 2.179 Sample Size 3624 3624 (a) For individual with income of $40000, he or she is found to consume 22 cups permonth. Based on the estimation result above, compute and comment on the incomeelasticity for high-class tea. (b) According to the result, would males drink more high-class tea? Explain. (c) If you add the price of coffee into the demand analysis, what would you expect onthe sign and significance of the price of coffee variable for the case of a rise in theprice of coffee? Explain. While you are not required to provide computation orexample, please use a demand-supply diagram for the market for tea to illustrate your expectation.

So9.

A large milling machine produces steel rods to certain specifications. The machine is considered to be running normally if the standard deviation of the diameter of the rods is at most 0.42 millimeters. The line supervisor needs to test the machine is for normal functionality. The quality inspector takes a sample of 45 rods and finds that the sample standard deviation is 0.49. What is the test statistic? Select one: а. 59.89 b. 48.63 с. 50.50 d. 52.45

b(Y)=400Y-6Y2 c(Y)=5y2

Economic topic. Show your work A weighing machine without any display was used by an average of 320 persons a day with a standard deviation of 50 persons. When an attractive display was used on the machine, the average for 100 days increased by 15 persons. Can we say that the display did not help much? Use a level of significance of 0.05?

Could you help me with this homework question? I got an answer of 22.9

12 A researcher reports survey results by stating that the margin of error for the 95% middle interval of the sample means is 44.75.  The population variance is assumed to be σ² = 18750.  The sample size used in this survey is ________.     a 53               b 44               c 36               d 31

19 The mean of z-scores in a data set       a is zero only when the x-values are balanced around the mean of x. b is greater than zero for data sets that have large outlying values. c is always equal to one.         d is always equal to zero

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c and d part hand write

SCCoast, an Internet provider in the Southeast, developed the following frequency distribution on the age of Internet users. Find the mean and the standard deviation. (Round squared deviations to nearest whole number and final answer to 2 decimal places.)   Age (years) Frequency 10 up to 20   3   20 up to 30   7   30 up to 40   18   40 up to 50   20   50 up to 60   12

ou would like to get the highest paying job possible after graduating from UCR and are currently deciding vhether to enroll in ECON 108 in the fall term or not. You find a sample of recent UCR graduates that majc n Economics (there are no double majors in the samples). You sampled 100 Economics majors that took ECON 108 and you find that the average starting salary is 72K dollars, with a sample standard deviation of 10K dollars. You sampled 75 Economics majors that did not take ECON 108 and you find that the average starting salary is 65K dollars, with a sample standard deviation of 15K dollars. Which of the following statements is most correct? O I am not very confident in the results of my hypothesis test because the range in which I fail to reject the null hypothesis is relatively large. O I want to be very confident in the results of my hypothesis test, so the range in which I fail to reject the null hypothesis is relatively large. O The range in which I fail to reject is small, so…

Question of the day. The mean weekly sales of the chocolate bar in candy stores was 146-3 bars per store. After an advertising campaign the mean weekly sales in 22 stores for a typical week increased to 153-7 and showed a standard deviation of 17-2. Was the advertising campaign successful?