Educator wants to find size of the sample to estimate standardized test scores with 95% confidence, being sure that result will be within 2 points of the true population mean µ. Standard deviation is equal to 12. (Don’t forget to round everything up – conservatively) ( You need to find Z-a/2,  Error, n).

Q: For bone density scores that are normally distributed with a mean of 0 and a standard deviation of…

A: From the given information, the mean is 0 and standard deviation is 1. a) The percentage of scores…

Q: The college president asks the statistics teacher to estimate the average age of the students at the…

A:

Q: What is the value of the 95th percentile

A: Given that X follows N(mean = 500, SD = 40), then Z = (X - mean)/SD follows N(0,1)

Q: he distribution of scores on the SAT is approximately normal with a mean of m= 500 and a standard…

A: Given that  SAT is approximately normal with a mean of m= 500 and a standard deviation of s = 100…

Q: The scores on the Accuplacer test and High School GPAs are normally distributed. The Accuplacer test…

A: It is given that: For the Accuplacer test, Meanμ1=40 Standard deviationσ1=9 For the GPAs,…

Q: A report by Twitter shows that the average cost of promoted tweets is 2.46 dollars per action.…

A: Given: μ = 2.46 σ = 1.76 n = 10 X = 2 Significance level α = 0.05 Formula Used: Z = X-μσn

Q: Majesty Video Production Inc. wants the mean length of its advertisements to be 31 seconds. Assume…

A: Let X be the random variable that is defined as the advertisement length.The provided details:

Q: A social scientist wants to estimate the average salary of office managers in a large city. She…

A: Solution: From the given information, confidence level is 0.95, σ=$1050 and E=$200.

Q: A researcher wants to estimate the mean serum cholesterol level for college age women.  In a past…

A: Obtain the large sample size needed. The large sample size needed is obtained below as follows: Use…

Q: Q4) The mean weight of 800 male students at a certain college is 70kg and the standard deviation is…

A: Given no. of students = 800 Mean (μ) = 70 Standard deviation (σ) = 10 We know that Z = X-μσ (i)…

Q: The population standard deviation for the body weights of the employees of a company is 10 pounds.…

A: Given information:Population standard deviation for the body weights of the employees, σ is 10Margin…

Q: The population standard deviation for the scores of a standardized test is 5 points. If we want to…

A:

Q: The electric cooperative needs to know the mean household usage of electricity by its non-commercial…

A:

Q: Dwight wants to estimate the mean calorie content in beets with 90% confidence.  He believes that…

A: The population standard deviation, sigma is 17. The z-critical value for the 90% confidence interval…

Q: The z-score of −2 tells us that x=14 is two standard deviations to the left of the mean. The…

A: Given that z score is -2. x=14 is two standard deviations to the left of the mean. That is, μ-2σ.…

Q: The scores on the Accuplacer test and High School GPAs are normally distributed. The Accuplacer test…

A:

Q: The scores on the Accuplacer test and High School GPAs are normally distributed. The Accuplacer test…

A:

Q: Samples of size 120 from Population 1 with mean 86 and standard deviation 10 and samples of size 75…

A: Calculate Standard Error using following formula

Q: n achieved by all the funds, is 8.20 and me empirical rule, what percentage of these andard…

A: Given : Mean = u = 8.20 Standard deviation = σ= 2.75

Q: researcher wants to estimate the average amount of calories in a large French Fries order in…

A:

Q: The mean pulse rate​ (in beats per​ minute) of adult males is equal to 69 bpm. For a random sample…

A: As the population standard deviation is not known, we will use a t-test. The value of the test…

Q: A researcher wants to investigate the effects of environmental factors on IQ scores. For an initial…

A: It is known that, the mean of the sampling distribution of sampling distribution, p-hat is equal to…

Q: A researcher is looking to estimate the mean LSAT score of law school applicants who completed their…

A: From the provided information, Margin of error (E) = 2 points Level of confidence = 99% Standard…

Q: Professor Harde assumes that exam scores are normally distributed and wants to grade "on the curve."…

A:

Q: Students claim that their teacher has been grading them more harshly than she has in the past.…

A: From the provided information, level of significance (α) = 0.05 Sample size (n) = 17 Sample mean…

Q: Claim: The mean pulse rate​ (in beats per​ minute) of adult males is equal to 69 bpm. For a random…

A: Given, Sample size = 149 Sample mean = 70.1 Sample standard deviation = 11.5   Population mean = 69…

Q: A manufacturer claims that the average lifetime of its lightbulbs is equal to 36 months. A random…

A:

Q: est the claim that the mean GPA of night students is larger than 3.2 at the .005 significance level.…

A: Given Information: Sample size (n) = 55 Sample mean (x¯) = 3.21 Standard deviation (s) = 0.04 Claim:…

Q: A marketing researcher wants to find a 95% confidence interval for the mean amount that visitors to…

A:

Q: The scores on the Accuplacer test and High School GPAs are normally distributed. The Accuplacer test…

A: Given: Accuplacer test Population mean μ1=30 Population standard deviation σ1=8 High school GPAs…

Q: A report by Twitter shows that the average cost of promoted tweets is 2.46 dollars per action.…

A: To test the α = 0.05 level of significance is there evidence to support the researcher's claim.

Q: The scores on the Accuplacer test and High School GPAS are normally distributed. The Accuplacer test…

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: The scores on the Accuplacer test and High School GPAS are normally distributed. The Accuplacer test…

A:

Q: the scores in a sample that has a standard deviation of z

A: The standard deviation is used to calculate the variability of the data set. It tells us about the…

Q: The mean of 200 items is 48 and their Standard Deviation is 3. Find: (i) The sum of all the items.…

A:

Q: The scores on the Accuplacer test and High School GPAs are normally distributed. The Accuplacer test…

A: The z score of 54 on the Accuplacer test is: z score=54-meansd=54-308=3   Let the GPA in high school…

Q: confidence that the sample mean is within 5 IQ points of the population mean?

A:

Q: of error, Claim: The standard deviation of pulse rates of adult males is more than 11 bpm. For a…

A:

Q: The biologist wants to estimate the average age of Coyotes in Tuolumne County. Her estimates from…

A: Given information- Population standard deviation, σ = 1.3 years Significance level(α) = 1- 0.95 =…

Q: he distribution of scores on the SAT is approximately normal with a mean of μ = 500 and a standard…

A:

Q: ​Claim: The mean pulse rate​ (in beats per​ minute) of adult males is equal to 69 bpm. For a random…

A: Given data Claim : The mean pulse rate​ (in beats per​ minute) of adult males is equal to 69 bpm.…

Q: Show the complete solution. A university dean wishes to estimate the average number of hours his…

A:

Q: The lengths of human pregnancies are normally distributed with a mean of u = 268 days and a standard…

A: Consider the provided question The lengths of human pregnancies are normally distributed with a mean…

Q: The scores on the Accuplacer test and High School GPAs are normally distributed. The Accuplacer test…

A: Here, μ = 35, σ = 9 and x = 24. The corresponding z-value is calculated using Central Limit Theorem…

Q: The biologist wants to estimate the average age of Coyotes in Tuolumne County. Her estimates from…

A: Given data,σ=1.3E=3z-value at 95% confidence is Zc=1.96n=?

Q: For an exam with a mean of = 74 and a standard deviation of s = 8, Mary has a score of X = 80, Bob’s…

A: Mean , μ = 74 Standard deviation , σ = 8 Mary's score , x = 80 Bob’s score , z = +1.50 Sue’s score =…

Q: Given : The average test score (µ) in 2020 of a Standardized Accounting Exam was 550 with a…

A: Hey there! Thank you for posting the question. Since there are multiple questions posted, we will…

Q: A store owner has found that a sample of customers purchased an average of 3.0 pounds of meats with…

A: Given that; x¯=3.0s=0.5 Now it is given that the store's meat scale is off by 0.1 lb. Let x1,…

Q: estimate the average number of hours his part-time instructors teach per week. The standard…

A: Given : Margin of error, ME = 1 population standard deviation, σ = 2.6…

Confidence Intervals

When we calculate intervals in probability and statistics, it can be simply termed as finding out a confidence interval. The confidence interval is usually calculated from the data set which is observed. The value of the parameter that needs to be calculated is present here only.