You want to obtain a sample to estimate how much parents spend on their kid's birthday parties. Based on previous study, you believe the population standard deviation is approximately a = $74.20. You would like to be 95 % confident that your estimate is within $2 of the mean spending on the birthday parties. How many parents do you have to sample? Give the minimum size that wil work.

Q: We notice a mean loss of 7 pounds in a sample of 11 dieters, with a standard deviation of three…

A: We first find the critical value for 95% confidence interval

Q: People with z-scores above 2.5 on an IQ test are sometimes classified as geniuses. If IQ scores have…

A: Given,   People with z-scores above 2.5 on an IQ test are sometimes classified as geniuses. If IQ…

Q: If the age distribution of customers at a major retail chain is thought to be bell-shaped with a…

A:

Q: For a sample of 300 students, you find that the mean GPA is 3.35 with a standard deviation of .21.…

A: Solution: From the given information, Standard deviation is 0.21 and n=300.

Q: For a sample of 18 cars, you find the standard deviation of the price is 6150 (measured in dollars).…

A: Given that, Sample size of cars n=18 Standard deviation of the price s=6150

Q: Assuming that the heights of college women are normally distributed with mean 65 inches and standard…

A: It is given that the mean is 65 and the standard deviation is 3.4.

Q: The range for a set of data is estimated to be 24. a. What is the planning value for the population…

A:

Q: A sociologist found that in a sample of 50 retired men, the average number of jobs they had during…

A: Given that  Sample size=50 , Mean=6.9 Population Standard deviation=2.3

Q: The summary data from study demonstrates a stronger relationship between how many minutes per day a…

A: Given : A standard deviation is a measure of how dispersed the data is in relation to the mean. Low…

Q: John wishes to estimate the population mean salary of college graduates who took a statistics course…

A: Solution: Note: Hello! As you have posted 2 different questions, we are answering the first question…

Q: A quantitative data set has size 40. At least how many observations lie within two standard…

A: Introduction: Suppose X is a random variable with expectation, μ and standard deviation, σ. Then,…

Q: If you want to be 95% confident of estimating the population mean to within a sampling error of ±5…

A: formula for the sample size :

Q: The scores of students on a standardized test are normally distributed with a mean of 300 and a…

A: X~N(μ=300, σ2=402) (A) P(220<X<380)= ?  (B) P(X<260)= ? (C) P(X>a)=0.25 a= ?  Note: This…

Q: Brewed decaffeinated coffee contains some caffeine. We want to estimate the amount of caffeine in 8…

A:

Q: Given a mean of 1,500 and a standard deviation of 53, calculate the value that is 2 standard…

A: Given that, Mean = 1500 Standard deviation = 53

Q: The mean grade on a final examination was 72 and the standard deviation was 9. The top 10% of the…

A: Mean(µ) = 72Standard deviations (σ) = 9

Q: A large number of applicants for admission to graduate study in business are given an aptitude test.…

A:

Q: A score that is 6 points below the mean corresponds to a z-score of z = -2.00. What is the…

A: Given: z-score = -2.00 Formula: Where,

Q: You want to be 95% confident that the sample standard deviation is within 40% of the population…

A: Given that  Confidence interval = 95% And Sample standard deviation is within 40% of the population…

Q: The water works commission needs to know the mean household usage of water by the residents of a…

A: GivenMargin of error(E)=0.15standard deviation(σ)=2.5Mean(μ)=15.2Confidence level(c)=80%

Q: Use the given information to find the minimum sample size required to estimate an unknown population…

A: Margin of error, M.E = $500 Confidence level (α) = 95% σ =$1500

Q: A score that is 6 points below the mean corresponds to a z-score of z = -1.50. What is the…

A: We have to find population standard deviation from given information. We need to use z score…

Q: (c) If the standard deviation remains at 0.5 ounce, what must the mean weight be for the company to…

A: Givenstandard deviation(σ)=0.5x=13 ounces

Q: You want to obtain a sample to estimate a population mean. Based on previous evidence, you believe…

A:

Q: A researcher wishes to estimate within $5 the average repair cost of for a refrigerator.  If she…

A: Given, Margin of error = 5 Standard deviation = 15.50   Critical value: Using the z-table, the…

Q: Past experience indicates that the standard deviation in the time it takes for a “fast lube”…

A:

Q: Given a scenario where n=100 and p=0.8, find the standard deviation.

A: In this case the sample size is n = 100 and p = 0.8.

Q: At Thomas Nelson Community College, the Pre-Test for Mathematics has 200 points on the test. The…

A:

Q: Mark was asked, "To what extent are you a Math person?" He rated himselfa 6 on a 7-point scale.…

A: Here use z score for  determining the statement correct or not

Q: A quantitative data set has a size of 50. At least how many observations lie within seven standard…

A: Suppose X is a random variable with expectation, μ and standard deviation, σ. Then, for any positive…

Q: John wishes to estimate the population standard deviation of salary of college graduates who took a…

A: Standard deviation is the positive square root of the mean of the squared deviations of given…

Q: Jamie would like to estimate the mean amount households in the small town of Ringwood spend on…

A: Given:Margin of error = E = $25Population standard deviation = σ = $288Confidence level = 95%

Q: A quantitative data set has size 50. At least how many observations lie within three standard…

A: The size of the data set is 50.

Q: The credit scores of 35-year-olds applying for a mortgage at Ulysses Mortgage Associates are…

A: (a) Obtain the credit score that defines the upper 5 percent. The credit score that defines the…

Q: The mean June midday temperature in Desertville is 36°C and the standard deviation is 3°C. Assuming…

A: Determine the number of days in June would be expected the midday temperature to be between 39°C and…

Q: The data set has size 40. Approximately how many observations lie within two standard deviations to…

A: 68-95-99.7-rule: Let X be an observation from a normal distribution, having mean µ and standard…

Q: If you want to be 95​% confident of estimating the population mean to within a sampling error of ±20…

A: Given information- Population standard deviation, σ = 100 Confidence interval = 0.95 Significance…

Q: The range for a set o data is estimated to be 60. a. What is the planning value for the population…

A: Here, Range=60 a) Planning value for the population standard deviation: Planning value=Range4=604=15…

Q: A quantitative data set has a size 50. At least how many observations lie within 3 standard…

A: Suppose X is a random variable with expectation, μ and standard deviation, σ. Then, for any positive…

Q: The range for a set of data is estimated to be 36.a. What is the planning value for the population…

A: a.

Q: On the final exam, your friend scored a 93 and you scored a 85. The scores are normally distributed…

A: Obtain the Z-score for the random variable X equals 85. The Z-score for the random variable X equals…

Q: A quantitative data set has size 60. At least how many observations lie within three standard…

A:

Q: According to Chebyshev's Teorem, at least what percentage of snake lengths are within K= 2.9…

A: The Chebyshev’s rule states that, for any quantitative data set and any real number greater than k,…

Q: On an exam with u = 52, you have a score of X = 56. Which value for the standard deviation would…

A: We have given that µ = 52 x = 56 z-score formula is given as  z =( x - μ )/σ

Q: A nurse at a local hospital is interested in estimating the birth weight of infants. How large a…

A:

Q: A successful basketball player has a height of 6 feet 3 ​inches, or 191 cm. Based on statistics from…

A: Given,a basketball player has a height of 6 feet 3 inchesand the Z-score =2.31

Q: me mean is 225 and the standard deviation is 28 for a normally distributed variable, what is the x…

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: Sixteen percent of the world's population is left-handed. A researcher claims that left-handed…

A: a) mean (p) = 0.16 , q = 1 - 0.16 = 0.84 , n =2100

Q: What are all the values that standard deviation "s" can possibly take?

A: Standard deviation S=x1;x2n-1and ,Standard deviation is the positive squarew root of the variance…