# Please do all questions… A cell phone battery manufacturer claims that one of their batteries for…

Please do all questions…

A cell phone battery manufacturer claims that one of their batteries for a particular cell phone will outperform a competitor’s equivalent brand. To establish this claim, a researcher selected samples of the two brands of batteries and perform accelerated tests on them in the lab under identical conditions. A random sample of 55 of the manufacturer’s battery was selected and placed on test. A corresponding random sample of 55 of the competitor’s battery was also put on test. The number of batteries lasting beyond 2000 hours (successes) and sample sizes are given in the following table. Manufacturer Competitor X2 = 44 n2= 55 = 41 n1 = 55 Step 1 of 2: Construct a 95 percent confidence interval for the difference in the proportions of batteries which lasted beyond 2000 hours for the manufacturer’s brand relative to the competitor’s A cell phone battery manufacturer claims that one of their batteries for a particular cell phone will outperform a competitor’s equivalent brand. To establish this claim, a researcher selected samples of the two brands of batteries and perform accelerated tests on them in the lab under identical conditions. A random sample of 55 of the manufacturer’s battery was selected and placed on test. A corresponding random sample of 55 of the competitor’s battery was also put on test. The number of batteries lasting beyond 2000 hours (successes) and sample sizes are given in the following table. Manufacturer Competitor I2 = 44 nz= 55 =41 n1= 55 Step 2 of 2: Interpret the correct answer from STEP 1 A quality control manager is comparing shipments of android tablets from two suppliers. Identify these suppliers as Supplier A and Supplier B. The manager randomly selects samples of tablets from two shipments, one from each supplier and tested them for defects. The sample information is shown in the following table. Supplier A n1=40 X1= 3 Supplier B n2= 30 X2 =1 Sample Size Number of Defectives Step 1 of 2: Construct a 99 percent confidence interval for the proportion of defectives from Supplier A – Supplier B. Tables Keypad Answer 10 Points a-0.0511 to 0.1344 -0.0622 to 0.1455 -0.0948 to 0.1782 -0.0455 to 0.1288 A quality control manager is comparing shipments of android tablets from two suppliers. Identify these suppliers as Supplier A and Supplier B. The manager randomly selects samples of tablets from two shipments, one from each supplier and tested them for defects. The sample information is shown in the following table. Supplier B nz=30 X2 = 1 Supplier A n1= 40 X1=3 Sample Size Number of Defectives Step 2 of 2: Interpret the correct answer from STEP 1 placed A company makes two types of batteries (Type A and Type B) for midsize electric cars. These two batteries are the distance (in miles) one of these midsize electric cars will cover before the batteries needed recharging. The summary information for the tests on these two battery types is given in the table. on test to determine Type A i4= 410 Type B 2395 S1 = 15 n1= 47 S2= 11 n2= 51 Step 1 of 2: Construct a 95 percent confidence interval for the difference of the mean life time before recharging. Consider (Type A- Type B). A company makes two types of batteries (Type A and Type B) for midsize electric cars. These two batteries are the distance (in miles) one of these midsize electric cars will cover before the batteries needed recharging. The summary information for the tests on these two battery types is given in the table. placed on test to determine C SI Турe A = 410 Туре В 2 = 395 S1= 15 S2= 11 п347 nz= 51 Step 2 of 2: Interpret the correct answer from STEP We were unable to transcribe this imagewas conducted to investigate the proportion of professors in colleges in a particular state who were involved with grant funded research. In a random sample of 125 male professors, 34 of them were involved with grant funded research. In a corresponding random sample of 95 female professors, 22 of them were involved with grant funded research. A study Step 2 of 2: Interpret the correct answer from STEP The budget director for a company is interested in comparing the daily travel expenses for the sales staff and the audit staff. The results of her study are presented below. Staff Sample Standard Deviation of Daily Travel Expenses $20 Sample Size Mean Daily Travel Expenses Sales $160 40 Audit 130 15 45 Step 1 of 3: Construct the 90% confidence interval for the true difference (Sales – Audit) in the means Tables Keypad 10 Points Answer a 22.39 to 37.57 22.40 to 37.58 22.41 to 37.59 23.63 to 36.37 The budget director for a company is interested in comparing the daily travel expenses for the sales staff and the audit staff. The results of her study are presented below. Staff Sample Standard Mean Daily Travel Expenses Sample Size Deviation of Daily Travel Expenses $20 $160 Sales 40 Audit 130 15 45 Step 2 of 3: Construct the 959% confidence interval for the true difference (Sales -Audit) in the means. Tables Keypad 10 Points Answer (22.40, 37.58) (22.38, 37.56) (22.41, 37.59) (22.39, 37.57) We were unable to transcribe this imageTwo different methods of teaching an elementary statistics course were . Identify these two methods as Method A and Method B. Both sections had to complete identical assignments, including homework, quizzes, exams, and writing assignments. At the end of the semester, the instructor wanted to compare the two teaching methods by analyzing the average percentages for the two classes by constructing a confidence interval for the difference of the two means. The summary information is given in the table. used to present the course materials to two large sections of the C Course Method A Method B 82 I291 S2= 8 n2=51 n1= 48 Step 1 of 2: Construct a 90 percent confidence interval for the difference in the average percentages for the two classes (Method A Method B). Note: Approximate the population standard deviations with the sample standard deviations Step 1 of 2: Construct a 90 percent confidence interval for the difference in the average percentages for the two classes (Method A- Method B). Note: Approximate the population standard deviations with the sample standard deviations. Treated Group Control Group =8.3 S1=0.7 n= 45 2 =3.4 S2= 1.3 nz= 45 Step 1 of 2: Construct a 99 percent confidence interval for the difference in the average time (in years) to death between the treated group and the control group. Note: Approximate the population standard deviations with the sample standard deviations. Treated Group i=8.3 Control Group i2 3.4 S1 = 0.7 n= 45 S2= 1.3 nz= 45 Step 2 of 2: Interpret the correct answer from STEP 1 The Lake Eerie Islands of northern Ohio are renowned for their fine wineries. Suppose a vintner of one of the Lake Eerie Islands would like to compare two pesticides, A and B, to see which protects the vines more from a certain disease infestation. To test effectiveness three long randomly selected rows were sprayed with A and three long randomly selected rows were sprayed with B. 500 vines were then randomly selected from among these rows and checked for disease infestation. The results are presented below. Number of Vines Number of Vines Insecticide Infested Examined 25 A 500 500 АП Step 1 of 2: Construct the 90% confidence interval for the difference between infestation rates of A-treated and B-treated vines. Tables Кeypad 10 Points Answer a-0.056 to -0.004 -0.058 to -0.002 -0.057 to -0,003 -0.059 to -0.001 The Lake Eerie Islands of northern Ohio are renowned for their fine wineries. Suppose a vintner of one of the Lake Eerie Islands would like to compare two pesticides, A and B, to see which protects the vines more from a certain disease infestation. To test effectiveness three long randomly selected rows were sprayed with A and three long randomly selected rows were sprayed with B. 500 vines were then randomly selected from among these rows and checked for disease infestation. The results are presented below. Number of Vines Number of Vines Insecticide Infested Examined A 500 25 B 500 40 Step 2 of 2: Construct the 95% confidence interval for the difference between infestation rates of A-treated and B-treated vines. Кeypad Tables Answer 10 Points (-0.063, 0.003) (-0.061, 0.001) (-0.062, 0.002) (-0.060, 0.000) When confidence intervals for the difference between two population means are constructed, if the population variances are unknown, they can be estimated by their respective sample variances for large enough sample sizes. True or false?