According to a study, suppose the probability that a randomly selected child aged 8–12 spends more than an hour a day online is 0.71. Let X be the number of children in a randomly selected group of 50 that spend more than an hour a day online. (a) Compute the expected value and standard deviation of X. (Round your answer to two decimal places.) expected value standard deviation (b) Fill in the missing quantity. (Round your answer to the nearest whole number.) There is an approximately 2.5% chance that ? or more children in the group spend more than an hour a day online.

Q: The average number of electronic messages received in a day on a smartphone is 15. If the standard…

A: Given information: μ=15σ=4

Q: A particular fruit's weights are normally distributed, with a mean of 347 grams and a standard…

A: From the provided information, Mean (µ) = 347 Standard deviation (σ) = 25 X~N (347, 25)

Q: Business Weekly conducted a survey of graduates from 30 top MBA programs. On the basis of the…

A: From the provided information,Mean (µ) = 162000Standard deviation (σ) = 36000Sample size (n) = 58

Q: Assume that adults have IQ scores that are normally distributed with a mean of μ = 100 and standard…

A:

Q: The average hourly charge of plumbers in the Denver area is $84.00 with a standard deviation of…

A: Let X= charges of plumbers in the Denver area Given that X follows a normal distribution with mean=…

Q: The percent of fat calories that a person consumes each day is normally distributed with a mean of…

A: The mean percent of fat calories that a person consumes each day μ= 35 Standard deviation σ = 10…

Q: Suppose that a category of world class runners are known to run a marathon (26 miles) in an average…

A: The known values are, μ=142,σ=13,n=49 The mean and standard deviation of sampling distribution of…

Q: The lifetime risk of developing pancreatic cancer is about one in 78 (1.28%). Suppose we randomly…

A: Given that, The lifetime risk of developing pancreatic cancer is about one in 78

Q: The average American man consumes 9.8 grams of sodium each day. Suppose that the sodium consumption…

A: Given data,μ=9.8σ=0.9Let X = the amount of sodium consumed

Q: The amount of time that people spend at Grover Hot Springs is normally distributed with a mean of 74…

A: (a)   Obtain the probability that a randomly selected person at the hot springs stays longer than 80…

Q: Assume that adults have IQ scores that are normally distributed with a mean of 96.9 and a standard…

A:

Q: The average number of pounds of red meat a person consumes each year is 196 with a standard…

A: Answer Sample size [n] =50Mean =196Standard deviation =22

Q: Assume that adults have IQ scores that are normally distributed with a mean 103.4 of and a standard…

A: IQ scores are normally distributed with a mean 103.4 and a standard deviation of 16.8.

Q: Business Weekly conducted a survey of graduates from 30 top MBA programs. On the basis of the…

A: X follows a Normal distribution with mean = 172000 and S.D = 41000 Then z=(x-mean)/SD =…

Q: Suppose that a category of world class runners are known to run a marathon (26 miles) in an average…

A: The Z-score of a random variable X is defined as follows: Z = (X – µ)/σ. Here, µ and σ are the mean…

Q: Business Weekly conducted a survey of graduates from 30 top MBA programs. On the basis of the…

A:

Q: A manufacturer makes thousands of ballpoint pens per day, and estimates that 3% are defective and…

A: If we have n trials each having two outcomes, say Success and Failure, trials being independent and…

Q: he IQ is normally distributed with a mean of 100 and a standard deviation of 15. Suppose one…

A: Given that  Mean=100 SD=15 X = IQ of an individual. The probability that a randomly selected person…

Q: Suppose that a category of world class runners are known to run a marathon (26 miles) in an average…

A: X¯ ~ N(μx¯ , σx¯) μx¯=μ=142 σx¯=σn=1349=1.86 N = Normal distribution

Q: In a certain state, two-fifths of all adults register as Democrats.  A random sample of 150 adults…

A: From the information, given thatLet the random variable X denotes the number of registered Democrats…

Q: Suppose that the annual rate of return for a common biotechnology stock is normally distributed with…

A:

Q: A baseball team has 31 players, 8 of whom bat left-handed. Suppose that the manager of this team is…

A: A baseball team has 31 players, 8 of whom bat left-handed. Suppose that the manager of this team is…

Q: Suppose a batch of steel rods produced at a steel plant have a mean length of 178 millimeters, and a…

A: From the provided information,Mean (µ) = 178Standard deviation (σ) = 12Sample size (n) = 76

Q: Suppose that a category of world class runners are known to run a marathon (26 miles) in an average…

A: The probability that the average of the sample will be between 144 and 149 minutes in these 49…

Q: Assume that blood pressure readings are normally distributed with a mean of 123 and a standard…

A:

Q: Find the probability that the mean height of the sample is greater than 58 inches.

A: Assume that the height of adult females in the United States is approximately normally distributed…

Q: Suppose that in a large population of women (aged 20 to 29-years-old) that the mean serum…

A: From the given information ,Population mean , 183Population standard deviation , 37sample size , n =…

Q: Find the probability that an individual man’s step length is less than 2.3 feet.

A: Suppose that the walking step lengths of adult males are normally distributed with a mean of 2.6…

Q: Suppose the distributions of arrival and service times were normal instead of exponential.  Let the…

A: The objective of this question is to estimate the long-run average number of people that would be in…

Q: normally distributed with a mean of $39,269 and a standard deviation of $2,550. The probability…

A:

Q: Business Weekly conducted a survey of graduates from 30 top MBA programs. On the basis of the…

A:

Q: Assume that for the population of all unemployed individuals in Minnesota, the population mean…

A:

Q: Business Weekly conducted a survey of graduates from 30 top MBA programs. On the basis of the…

A:

Q: Assume that adults have IQ scores that are normally distributed with a mean of 104 and a standard…

A: Solution Let "X" be the IQ score of adults.