Q1. John Kleman is the host of the KXYX Radio AM drive-time news in Denver. During his morning program, John asked listeners to call in and discuss current local and national news. This morning, john was concerned with the numbers of hours children under 12 years of age watched TV per day. The last 5 callers reported that their children watched the following numbers of hours of hours of TV last night.
3.0 3.5 4.0 4.5 3.0
Would it be reasonable to develop a confidence interval from these data to show the mean number of hours of TV watched? If yes, construct an appropriate confidence interval and interpret the result. If no, why would a confidence interval not be appropriate?
No we have very less number of data points to conclude what will be the confidence interval of mean and even if we find using this data it will not be relevant.
Q.2 A manufacture of cell phone batteries wants to estimate the useful life of it's battery (in thousand of hours.) The estimate is the be within 0.10 (100) hours. Assume 1 95 percent level of confidence and that the standard deviation of the useful life of the battery is 0.90 (900 hours). Determine the required sample size.
Estimate is to be within 0.1 , and so it's the deviation from the mean and the 95 % value will be 1.96 and the standard deviation is 0.9 ,
So 0.1 /0.9 * root (n) = 1.96 , so n = (1.96*9)^2 = 311
Q3. In a sample of 200 residents of Georgetown country, 120 reported they believe that country real estate taxes were too high. Developed a 95% confidence interval that proportioned of residents who believe the tax rate is too high. Would it be reasonable to conclude that the majority of the taxpayers feel that the text says I too high.
The proportion of people who believe yes is 120/200 = 0.6 . So when we calculate the test stat based on the proportion , it is
*1.96 (P*(1-p)/n)^0.5 = 0.067 , and so the confidence interval would include the 0.6 value so we can say that yes major tax payers feels it is high
Q A buffalo, your cola distributor is featuring a super-special sale on 12-packs. She wonders where in the grocery store to place the cola for maximum attention. Should it be near the front door of the grocery stores. In the cola section, at the checkout registers, or near the milk and other dairy products? Four stores, with similar totals sales coopters, or near the milk and other dairy products?for stores with stacks near the front door, in another they were placed near the checkout registers, and so on. Sales were checked at specified times in each store exactly four minutes. The results were:
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Soft Drink
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New Registers
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Dairy Section
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Selection
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$5
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$7
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$10
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10
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10
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9
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12
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9
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6
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4
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4
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11
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9
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5
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7
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The Buffalo distributor wants to find out whether there is a difference in the mean sales for cola stacked at the four locations in the stores. Use the .05 Significance level