1. AutoTrader.com would like to test if a difference exists in the age of three
ID: 3232971 • Letter: 1
Question
1. AutoTrader.com would like to test if a difference exists in the age of three different types of vehicles currently on the road--trucks, cars, and vans. The following data represent the age of a random sample of trucks, cars, and vans.
Using = 0.05, the conclusion for this hypothesis test would be that because the test statistic is
D. more than the critical value, we can conclude that there is a difference in the average age of trucks, cars, and vans currently on the road
2. The R.D. Wilson Company makes a soft drink dispensing machine that allows customers to get soft drinks from the machine in a cup with ice. When the machine is running properly, the average number of fluid ounces in the cup should be 14. Periodically the machines need to be tested to make sure that they have not gone out of adjustment. To do this, six cups are filled by the machine and a technician carefully measures the volume in each cup. In one such test, the following data were observed:
D. The null can be rejected because the majority of the sample values exceed 14.
3. Suppose Burger King has run a major advertising campaign in the hopes of increasing monthly sales. To investigate the effectiveness of this campaign, Burger King randomly selected six restaurants and recorded the monthly sales before and after the advertising. The following data represents these sales figures in thousands of dollars.
If Population 1 is defined as sales after the advertising campaign and Population 2 is defined as sales before the advertising campaign, and using = 0.05, which one of the following statements is true?
Trucks Cars Vans 12 8 3 8 7 7 9 10 6 11 7 8 Restaurant 1 After $123 $122 $145 $156 $160 $134 Before $107 $110 $143 $168 $145 $125Explanation / Answer
Q.1 Null Hypothesis : There is no significant difference in age difference between age groups of tuck, car and vans.
Alternative Hypothesis : Ha : There is significant difference in age difference between age groups of tuck, car and vans.
ANOVA Table
F > Fcritical
So we can reject the null hypothesis as F- statistic is more than the critical value, we can conclude that there is a difference in the average age of trucks, cars, and vans currently on the road. Option D is correct.
Q.2
Null Hypothesis : H0 : There is no significant difference in average number of fluid ounces in the cup from historical rate of 14 ounces
Alternative Hypothesis : Ha : There is significant difference in average number of fluid ounces in the cup from historical rate of 14 ounces
Mean of the given sample xbar = 14.022
Standard Deviation s = 0.1837
so standard error of population mean se0 = (s/ n) = 0.1837/ 6 = 0.075
Test Statistic:
t = (xbar - 14)/ se0 = (14.02 - 14)/ 0.075 = 0.265
so tcritical for dF = 5 and alpha = 0.05 tcritical = 2.571
as t < tcritical so we cannot reject the null hypothes is null hypothesis cannot be rejected since the test statistic is approximately t = 0.20, which is not in the rejection region. Option B is correct.
Anova: Single Factor SUMMARY Groups Count Sum Average Variance Trucks 4 40 10 3.33 Cars 4 32 8 2 Vans 4 24 6 4.67 ANOVA Source of Variation SS df MS F P-value F crit Between Groups 32 2 16 4.8 0.038131 4.256495 Within Groups 30 9 3.333333 Total 62 11Related Questions
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