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- 1. The test scores of an Engineering Mechanics class with 800 students are distributed normally with a mean of 75 and a standard deviation of 7. a. What percentage of the class has a test score between 68 and 82? b. Approximately how many students have a test score between 61 and 89? c. What is the probability that a student chosen at a random has a test score between 54 and 75? d. Approximately how many students have a test score greater than or equal 96A. The distribution of results from a cholesterol test has a mean of 180 and a standard deviation of 20. A sample size of 40 is drawn randomly. Find the probability that the sum of the 40 values is less than 6,900. (Round your answer to four decimal places.) B. The distribution of results from a cholesterol test has a mean of 180 and a standard deviation of 20. A sample size of 40 is drawn randomly. Find the sum that is one standard deviation below the mean of the sums. (Round your answer to two decimal places.) C. The distribution of results from a cholesterol test has a mean of 180 and a standard deviation of 20. A sample size of 40 is drawn randomly. Find the sum that is 1.4 standard deviations below the mean of the sums. (Round your answer to two decimal places.)Please show the steps to solve the problems 28 a, b, and c.
- A particular fruits’ weights are normally distributed, with a mean of 312 grams, and a SD of 20 grams. If you pick 6 fruits at random, then 16% of the time, their mean weight will be greater than how many grams? (Give the answer to the nearest gram)Two gamblers bet $1 each on the successive tosses of a coin: i.e., at each coin toss, player 1 pays $1 to player 2 if the coin shows ‘Heads’, and player 2 pays $1 to player 1 if the coin shows ‘Tails’. What is the mean and the standard deviation of the total winnings (measured in $, winnings can be negative) of player 1 after 6 tosses?The U.S. Fish and Wildlife Service reported that the lengths of six-year-old rainbow trout in the Arolik River in Alaska are normally distributed with a mean of 481 millimeters and standard deviation of 41 millimeters. If a six-year-old rainbow trout from the Arolik River is selected at random, what is the probability it's length is more than 500 millimeters? Question 5 options: 0.1588 0.3215 0.4576 0.6785
- e) Suppose that weekly household expenditures on petrol are normally distributed, with a mean of $120 and a standard deviation of $50. i. A family is randomly selected. Find the probability that this family spends more than $245 per week on petrol? A 2.5 B 0.0062 C 0.9938 D 0.0202 ii. The government wants to promote public transport and will award a prize to the families who spend the lowest amount on petrol. If the government only wants to give a prize to 10% of households, what is the most that a family is allowed to spend on petrol each week to obtain the prize? A $56 B $184 C $3.50 D $217.60 In a sample of 25 families, what is the probability that the average weekly expenditure on petrol will be less than $105? ii. A 0.0668 B 0.9332 C 0.3821 D 0.61791. Service time for a customer coming through a checkout counter in a retail store is a random variable with the mean of 10.0 minutes and standard deviation of 4.0 minutes. Suppose that the distribution of service time is fairly close to a normal distribution. Suppose there are two counters in a store, n₁ = 41, customers in the first line and m₂ = 51 customers in the second line. Find the probability that the difference between the mean service time for the shorter line and the mean service time for the longer X₂ one ¹2 is more than 0.4 minutes. Assume that the service times for each customer can be regarded as independent random variables.A simple random sample of 64 observations was taken from a large population. The population standard deviation is 120. The sample mean was determined to be 320. The standard error of the mean is _____.
- 1) The mean and standard deviation of a population are 200 and 20, respectively.The probability of selecting one data value less than 190 is ____ %. (Round answer to the nearest percent (whole number). Do not write the % sign.) 2) A. C. Neilsen reported that children between the ages of 2 and 5 watch an average of 25 hours of television per week. Assume the variable is normally distributed and the standard deviation is 3 hours.If 20 children between the ages of 2 and 5 are randomly selected, the number of children in the sample who watch at least 25.2 hours of television is? Give answer to the nearest whole number, not a percent. 3) A. C. Neilsen reported that children between the ages of 2 and 5 watch an average of 25 hours of television per week. Assume the variable is normally distributed and the standard deviation is 3 hours.If 20 children between the ages of 2 and 5 are randomly selected, the number of children in the sample who watch at most 22.5 hours of television is? . Give…2. Ms. Palac, a sociologist, made a study on the age in years of a woman at the time of her first marriage. She randomly selected a sample of 24 and 21 married women from Village A and Village B, respectively. The following data are the mean and standard deviation for each group: Village A: x = 18.63 and s = 5.54 Village B: x = 24.90 and s = 5.54 Test the hypothesis that the women in Village A get married younger than women in Village B. Use 0.10 significance level. Step 1: Null and Alternative Hypothesis Ho: Ha: Step 2: Level of Significance and appropriate test statistic Step 3: Determine the Critical Region Degrees of Freedom (df): Critical Region: Step 4: Compute the z or t value Computations: Step 5: Decide whether to accept or reject Ho Step 6: ConclusionIn a recent study, the Centers for Disease Control and Prevention reported that the diastolic blood pressures of adult men in the United States are normally distributed with a mean of 80.5 and standard deviation of 9.9. If an adult male is selected at random, what is the probability his diastolic blood pressure is above 90? Question 2 options: 0.1782 0.8218 0.1686 0.8314