QUESTION 1.1

The Normal Standard Distribution is a special type of normal distribution that has a mean of 1 and a standard deviation of zero.

Choose one ? 2 points

True

False

QUESTION 1.2

The Normal Standard Distribution can be used with any distribution, as long as it is a normal distribution.

Choose one ? 2 points

True

False

Answer the following questions using the applet. Leave your answers EXACTLY as the applet gives them to you Do NOT round. Probabilities of Z Scores Z-Score #1 :- Z-Score #2:] (If used, must be > ZScore #1) Standard Normal Distribution with Mean = 0 and Standard Deviation = 1 Z Score Calculator Point of Interest (X): Standard Deviation:- 2 Score = (500-600)/40 = 2.5 E Probability of Score In Between = ? Demonstration of Probabilities of Z-Scores plus Z-Score Calculator DES = ? Prob. of Score less than Z-Score #1 = 0.8413 Prob. of Score more than ZScore #1 = 0.1587 F'I LJ QUESTION 2.1 An engineer is going to redesign an ejection seat for an airplane. The seat was designed for pilots weighing between 140 lbs. and 190lb. The new population of pilots has normally distributed weights with a mean of 158 lbs. and a standard deviation of 27.2 lb. Find the probability that a pilot weight is between 140 lbs. and 190 lbs. The probability that the pilot weighs between 140 and 190 pounds is A Enter an answer - 5 points QU ESTION 2.2 Scores on a Statistics final are normally distributed, with a mean of 78 and a standard deviation of 12. A student takes his final; find the probability that the student gets a score is less than 71. Then, find the probability that the student score at least a 95. The probability that the student scores less than 71 is A The probability that the student scores are 95 or more is B Enter an answer - 5 points QU ESTION 2.3 A gaming developer company conducted a survey and found that families with teenagers spend, on average $238.92 in playing video games (including downloads, streaming, physical copies, and in-game purchases) a year. Assume the standard deviation is $31.38. Assume the variable is normally distributed. (a) Find the probability that a family spends over $290 in playing video games every year. (b) Find the probability that a family spends less than $150 in playing video games every year. (c) Find the probability that a family spends between $175 and $255 in playing video games every year. (a) The probability that a family spends over $290 in playing video games every year is A (b) The probability that a family spends less than $150 in playing video games every year is B (c) The probability that a family spends between $175 and $255 in playing video games every year is C Enter an answer - 5 points QUESTION 3.1 The average waiting time to be seated for dinner at a popular restaurant is 23.8 minutes with a standard deviation of 6 minutes. What is the probability that 20 people will wait less than 21 minutes? Leave your answer exactly as it is taken from the table. The probability that 20 customers will wait less than 21 minutes to be seated is A Enter an answer ' 5 points QUESTION 3.2 A survey found that students at US. universities, on average, have a GPA of 3.342 with a standard deviation of 0.9. If 19 students are randomly selected, what is the probability that their mean GPA is at least 3.8? Leave your answer exactly as it is calculated in the calculator. The probability that their GPA has a mean of at least 3.8 is A Enter an answer - 5 points QUESTION 3.3 Full-time Ph.D. students receive a stipend average of$15,837 per year with a standard deviation of $1600 find the probability that 25 full time PhD students make between $15,000 and $16,500. The probability that 25 full time PhD student receive a stipend between $15,000 and $16,500 is A Enter an answer - 5 points QUESTION 5.1 Find a 95% confidence interval estimate of the mean weight of all women based on a sample of 60 women with a mean sample weight of 150.27. From past studies, the standard deviation is known to be 30.87. Write your answer EXACTLY as is given by Excel. Do not round. The lower limit is A pounds. The upper limit is B pounds. Enter an answer . 5 pointsQUESTION 5.2 A survey of 300 people between the ages of 1 8 and 25, showed that they spend, on average, $137.23 on entertainment each month. The population standard deviation is known to be $31.44. Construct a confidence interval for the mean amount of money people 18 to 25 spend on entertainment each month. Use a confidence level of 99%. Write your answer EXACTLY as is given by Excel. Do not round. The lower limit is $ A The upper limit is $ B Enter an answer - 5 points QUESTION 6.1 Construct a confidence interval using a sample ofsize 15, with a sample standard deviation of l .45, a sample mean of 5.3, and a confidence level of 90%. Write your answer EXACTLY as is given by Excel. Do not round. The lower limit is A The upper limit is B Enter an answer - 5 points QUESTION 6.2 Salaries of 25 college graduates who took a statistics course in college have a mean of $59,600. Assuming the population standard deviation of$19,055, construct a 95% confidence interval for estimating the population mean. Write your answer EXACTLY as is given by Excel. Do not round. The lower limit is $ A The upper limit is $ B Enter an answer ' 5 points QUESTION 7.1 In a survey of 3500 adults (18 and over) who reside in California, 2339 were found to like outdoor sports. Construct a confidence estimate for the true proportion of adults who live in California and who like outdoor sports. Use a confidence level of 99% Write your answer EXACTLY as is given by Excel. Do not round. The lower limit is A The upper limit is B Enter an answer - 5 points QUESTION 7.2 In a Gallup poll of 2870 randomly selected adults, 64% said that they played Video games at least twice a week. Construct a 95% confidence interval estimate for the proportion of adults who play Video games twice a week. Write your answer EXACTLY as is given by Excel. Do not round. The lower limit is A The upper limit is B Enter an answer - 5 points QUESTION 8.1 A researcher wants to investigate the number of hours a week a typical college student dedicates to study. From past studies, we know that the standard deviation of similar studies is 3.1 hours. How many students should be surveyed if we want to be accurate within 05 hours. Use a 95% confidence level. Write your answer EXACTLY as is given by Excel. Do not round. We need to survey a minimum of A students. Enter an answer - 5 points QUESTION 8.2 An advertising company wants to investigate the mean number of hours spent by an adult (40 and older) using Facebook. How many adults 40 and older need to be surveyed by this company? From past studies, we know that the standard deviation is 4.2 hours. We want to be accurate within 1 hour. Use a confidence level of 90%. Write your answer EXACTLY as is given by Excel. Do not round. The company needs to survey a minimum of A adults (40 and older). Enter an answer - 5 points QUESTION 9.1 Find the sample size needed to estimate the percentage of people who have at least one pet at home. Use a 2.3% margin of error; use a confidence level of 95%. Write your answer EXACTLY as is given by Excel. Do not round. The minimum sample size needed is A Enter an answer - 5 points QUESTION 9.2 Last yea r, a survey found that 71% of young adults enjoy at least 1 energy drink every week. An energy drink company wants to verify if this fact still holds. How many young adults should this company survey to estimate the true proportion of young adults who drink energy drinks at least once a week ifthey want to be 99% confident that the estimate is within 25%? The company should survey a minimum of A young adults. Enter an answer ' 5 points