A manager of a computer store knows that 19% of PC sold out returned to his store for repair within one year. Five of these PCs, whose characteristic can be assumed to be independent of each other, are sold out. (i) What is the probability that at most two of these PCs have returned for repair? (ii) Find the mean number of PCs returned for repair and also find its variance.
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A manager of a computer store knows that 19% of PC sold out returned to his store for repair within one year. Five of these PCs, whose characteristic can be assumed to be independent of each other, are sold out. (i) What is the probability that at most two of these PCs have returned for repair? (ii) Find the mean number of PCs returned for repair and also find its variance.
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- One sample has n=7 and SS=35 and a second sample has n =17 and SS =45. What is the pooled variance for these two samples?Two surfers and statistics students collected data on the number of days on which surfers surfed in the last month for 30 longboard (L) users and 30 shortboard (S) users. Treat these data as though they were from two independent random samples. Test the hypothesis that the mean days surfed for all longboarders is larger than the mean days surfed for all shortboarders (because longboards can go out in many different surfing conditions). Use a level of significance of 0.05. Longboard: 4,8,8,4,7,7,10,6,8,10,12,11,9,15,11,16,12,9,12,18,19,15,11,15,19,20,9,23,21,23 Shortboard: 6,4,4,6,7,7,8,9,4,7,8,5,9,7,4,15,11,10,13,12,11,14,9,11,12,16,9,20,22,11 Determine the hypotheses for this test. Choose the correct answer below. O A. Ho: PL=Ps O B. Ho: HL Hs O F. Ho: HL> Hs Ha: HL # Hs Ha: HL = Hs Find the test statistic for this test. t= (Round to two decimal places as needed.) Find the p-value for this test. p-value = (Round to three decimal places as needed.) What is the conclusion for this…Two surfers and statistics students collected data on the number of days on which surfers surfed in the last month for 30 longboard (L) users and 30 shortboard (S) users. Treat these data as though they were from two independent random samples. Test the hypothesis that the mean days surfed for all longboarders is larger than the mean days surfed for all shortboarders (because longboards can go out in many different surfing conditions). Use a level of significance of 0.05. Longboard: 4,9,8,4,9,8,8,6,7,9,11,11,11,13,12,16,14,9,11,18,20,15,10,16,20,20,8,20,21,23 O Shortboard: 6,4,4,6,8,8,6,9,4,6,7,5,9,7,4,16,13,11,13,13,11,15,10,10,13,14,11,21,21,12 Determine the hypotheses for this test. Choose the correct answer below. O A. Ho: HL = Hs O B. Ho: HL = Hs OC. Ho: HL # Hs Ha: HL Hs O F. Ho: HL = Ps Ha: HL = Ps Ha: HL = Hs Ha: HL > Hs Find the test statistic for this test. t = (Round to two decimal places as needed.) Find the p-value for this test. p-value = (Round to three decimal places…
- Three students, Linda, Tuan, and Javier, are given five laboratory rats each for a nutritional experiment. Each rat's weight is recorded in grams. Linda feeds her rats Formula A, Tuan feeds his rats Formula B, and Javier feeds his rats Formula C. At the end of a specified time period, each rat is weighed again, and the net gain in grams is recorded. Using a significance level of 10%, test the hypothesis that the three formulas produce the same mean weight gain. (Let 1 = Linda's rats, 2 = Tuan's rats and 3 = Javier's rats.) Weights of Student Lab Rats Linda's rats Tuan's rats Javier's rats 43.0 46.9 51.1 38.5 40.1 40.4 40.7 38.4 37.1 45.8 45.7 44.8 37.8 43.6 47.7 Part (a) State the null hypothesis. H0: ?1 = ?2 = ?3 H0: At least two of the group means ?1, ?2, ?3 are not equal. Part (b) State the alternative hypothesis. Ha: ?1 = ?2 = ?3 Ha: At least two of the group means ?1, ?2, ?3 are not equal. Part (c) Enter an exact number as an…A study of college football games shows that the number of holding penalties assed has a mean of 2.2 penaltiesSuppose a sample of n = 160 observations has a mean of 13.6 and a variance of 6.8. If each value in the sample is multiplied by 4 and then 20 is added, what would be the variance of the new sample values?
- Need help with parts (a) to (d) on this Intro to Probability and Statistics homework problem. Make sure the answers you provide are lengthy. Don't give short answers. Also, make sure your handwriting is neat and readable. Statistically speaking, the typical romantic couple spends 3 hours of qualitytime together each day, with a variance of 1.5 hours. During my teenageyears, I was under the assumption that a friend and I were a couple, but sherecently pushed back on that claim. So, I logged our time spent together over aperiod of 92 days. As it turned out, we spent 2.65 hours together on a typicalday, again with a variance of 1.5 hours. Assuming that all of the time we spendtogether is “quality” and that relationship time spent is governed by the normaldistribution, do I have sufficient statistical evidence to claim that we were, infact, in a romantic relationship? (a) Find and interpret the z-score of our time spent together, specificallyreferencing what information the sign…Part I A bakery sells homemade bread by the loaf and sales are uniformly distributed between 200 and 600 loaves per day. a. Find the probability of selling 240 loaves on a given day. b. Find the probability of selling between 250 and 260 loaves per day Part II The golf balls produced by TruGolf have a mean distance of 250 meters and a variance of 625 meters. c. How large a sample of TruGolf balls should be taken if they want to estimate with 90% confidence the mean distance to within 8 meters? d A random sample of 40 balls from TruGolf are selected. Find the Bound of Error when the confidence level is 95% for TruGolfSuppose that, for one semester, you can collect the following data on a random sample of college juniors and seniors for each class taken: a standardised final exam score, percentage of lectures attended, a dummy variable indicating whether the class is within the student’s major, cumulative grade point average prior to the start of the semester, and SAT score. If you pool all of the data and use OLS, what are you assuming about unobserved student characteristics that affect performance and attendance rate and What roles do SAT score and prior GPA play in this regard?
- A father is concerned that his teenage son is watching too much television each day, since his son watches an average of 2 hours per day His son says that his TV habits are no different than those of his friends. Since this father has taken a stats class, he knows that can actually test to see whether or not his son is watching more TV than his peers The father collects a random sample of watching times from boys at his son's high school and gets the following data: 1.9, 2.3, 2.2, 1.9, 1.6, 2.6, 1.4, 2.0, 2.0, 2.2 Find a 95% confidence interval for the true mean number of hours teenagers at that school watch TV. a. Confidence Interval b. ConclusionWhat percentage of Contra Costa County adults supports a ban on assault-style weapons? Suppose that we survey a random sample of 100 adults living in Contra Costa County and find that 62% support a ban on assault-style weapons. According to a 2015 study by the Pew Research Center, 57% of U.S. adults favor a ban on assault-style weapons. Assuming that the variability in random samples will be the same in Contra Costa County as in the U.S., find the 95% confidence interval to estimate the proportion of CCC adults that favor a ban on assault-style weapons. g. Are we confident that the percentage of Contra Costa County residents that supports a ban is greater than the percentage nationwide as reported by the Pew Research Center? Why or why not?One-way or two-way refers to the number of independent variables (IV's) in your Analysis of Variance test. One-way has one independent variable (either discrete or continuous) and two-way has two independent variables (either discrete or continuous). For example, a one-way Analysis of Variance could have one IV (brand of cereal) and a two-way Analysis of Variance has two IV's (brand of cereal, calories). O True O False
