Homework Questions 5.3 1. A distribution of values is normal with a mean of XXXXXXXXXXand a standard deviation of 45.7 Find the probability that a randomly selected value is less than 1528.7 P (X...

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Homework Questions 5.3 1. A distribution of values is normal with a mean of 1493.5 and a standard deviation of 45.7 Find the probability that a randomly selected value is less than 1528.7 P (X < 1528.7)="_________________" *enter="" your="" answer="" as="" a="" number="" accurate="" to="" 4="" decimal="" places.="" *="" note="" all="" z-scores="" must="" be="" rounded="" to="" the="" nearest="" hundredth*="" 2.="" a="" distribution="" of="" values="" is="" normal="" with="" a="" mean="" of="" 822.2="" and="" a="" standard="" deviation="" of="" 45.1="" find="" the="" probability="" that="" a="" randomly="" selected="" value="" is="" greater="" than="" 935.4="" p="" (x=""> 935.4) = ________________ *Enter your answer as a number accurate to 4 decimal places. * Note all z-scores must be rounded to the nearest hundredth* 3. A distribution of values is normal with a mean of 684.5 and a standard deviation of 27.5 Find the probability that a randomly selected value is between 643.8 and 700.2 P (643.8 < x="">< 700.2)="______________" *enter="" your="" answer="" as="" a="" number="" accurate="" to="" 4="" decimal="" places.="" *="" note="" all="" z-scores="" must="" be="" rounded="" to="" the="" nearest="" hundredth*="" 4.="" the="" number="" of="" miles="" a="" certain="" type="" of="" brake="" pad="" will="" last="" is="" normally="" distributed="" with="" a="" mean="" of="" 56000="" miles="" and="" standard="" deviation="" 2590="" miles.="" find="" the="" probability="" that,="" if="" you="" install="" this="" type="" of="" brake="" pad,="" it="" will="" last="" more="" than="" 59315="" miles.="" p(x=""> 59315) = _________________ *Enter your answer as a number accurate to 4 decimal places. * Note all z-scores must be rounded to the nearest hundredth* 5. The heights of women aged 20-29 are normally distributed with mean 65.7 inches and standard deviation 3.3 inches. What percent of women are below 59.7 inches? Round to the nearest hundredth of a percent? _________________ *Enter your answer as a percent rounded to the nearest hundredth*Note: all z-scores must be rounded to the nearest hundredth* 6. Statista reported in 2014 that the mean number of Facebook friend for 18 to 24-year old’s was 649. Assuming the distribution is normal with mean 649 friends and standard deviation 120 friends, what is the probability that a randomly selected 18 to 24-year-old will have between 435 and 985 friends? P (435< x="">< 985)="_______________" *enter="" your="" answer="" as="" a="" number="" accurate="" to="" 4="" decimal="" places.="" *note:="" all="" z-scores="" must="" be="" rounded="" to="" the="" nearest="" hundredth*="" 7.="" suppose="" that="" a="" brand="" of="" lightbulb="" lasts="" on="" average="" 2628="" hours="" with="" a="" standard="" deviation="" of="" 138="" hours.="" assume="" the="" life="" of="" the="" lightbulb="" is="" normally="" distributed.="" calculate="" the="" probability="" that="" a="" particular="" bulb="" will="" last="" from="" 2191="" to="" 3064="" hours?="" p="">< x=""><3064) =="" _____________="" *enter="" your="" answer="" as="" a="" number="" accurate="" to="" 4="" decimal="" places.="" *="" note="" all="" z-scores="" must="" be="" rounded="" to="" the="" nearest="" hundredth*="" 8.="" suppose="" a="" drive="" for="" a="" pga="" tour="" golfer="" is="" 316.93="" yards="" with="" a="" standard="" deviation="" of="" 16.5="" yards.="" find="" the="" probability="" that="" a="" random="" drive="" will="" travel="" more="" than="" 317.9="" yards.="" p(x=""> 317.9) = _____________ *Enter your answer as a number accurate to 4 decimal places. *Note: all z-scores must be rounded to the nearest hundredth* 9. Assume that the readings at freezing on a batch of thermometers are normally distributed with a mean of 0 degree Celsius and a standard deviation of 1.00 degree Celsius. A single thermometer is randomly selected and tested. Let X represent the reading of this thermometer at freezing. What reading separates the highest 33.36% from the rest? c= ______ degree Celsius 6.1/6.2 Homework 1. Random samples of size 47 are drawn from a population with mean 138.4 and standard deviation 18.3. Find the mean and the standard deviation of the sample mean. Round to four decimal places. Mean = _________ Standard Deviation = ___________ *Enter your answer as number accurate to 4 decimal places* 2. Random samples of size 102 are drawn from a population with mean 97.7 and standard deviation 19.4. Find the mean and the standard deviation of the sample mean. Round to four decimal places. Mean= ______________ Standard Deviation= ___________ 3. A population is normally distributed with mean 23.9 and standard deviation 3.6. Find the probability that a sample of 9 values taken from this population will have a mean less than 24? ____________ *Note: all z-scores must be rounded to the nearest hundredth* 4. A manufacturer knows that their items have a normally distributed length, with a mean of 18 inches, and standard deviation of 3.6 inches. If 25 items are chosen at random, what is the probability that their mean length is less than 18.4 inches? _______________ 5. A manufacturer knows that their items have a normally distributed lifespan, with a mean of 13.9 years, and standard deviation of 0.6 years. If you randomly purchase 16 items, what is the probability that their mean life will be longer than 14 years? __________________ 6. A particular fruit’s weights are normally distributed, with a mean of 262 grams and a standard deviation of 30 grams. If you pick 16 fruit at random, what is the probability that their mean weight will be between 240 grams and 253 grams? ______________ 7. The average GPA at a college is 3.03 with a standard deviation of 0.5 If 42 students are selected at random, what is the probability that their average GPA will be between 2.76 and 3.2? _____________ 8. From 1985 to 2006, the average height of an NBA player was 6 foot 7 (79 inches). Suppose the distribution is approximately normal and the standard deviation is 1.5 inches. What is the probability that, of 39 NBA players selected at random, their average height is more than 79 inches? ______________ 9. IQ scores are normally distributed with a mean of 98 and standard deviation of 5. In a sample of 41 people, what is the probability that their average IQ score does not differ from the mean by more than two points? __________________ 10. Mathematics majors generally have one of the highest starting salaries. Suppose the average starting salary for mathematics majors is $45000 with a standard deviation of $3600. Find the probability that 33 mathematics majors have an average starting salary less than $45795 thousand? ______________