Find the mean and variance of the r.v. X if it has p.m.f. P(X=1)=0.2 , P(X=2)=0.3 and P(X=3) = 0.5 ?
Q: What does a z-score of –1.5 mean? A.The mean is 1.5 standard deviations less than the measurement.…
A: 3. z-score: The z score determines how far the individual measurement is from the value of mean. If…
Q: Use z scores to compare the given values. Based on sample data, newborn males have weights with a…
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: a) If a man is 75 inches (6 feet 3 inches) tall, what is his z-score (to two decimal places)?…
A: Hi, the question has multiple sub-parts. As per the guidelines I am obliged to answer first three…
Q: Suppose that a random sample of size 20 is taken from a normal distribution with unknown mean and…
A: Sample size, Variance, Sample mean, The posterior distribution: Posterior mean, Posterior variance,…
Q: What is the explained variance and unexplained variance. correlation coefficient, is .771…
A: Determine the value of explained variance. The value of explained variance is determined below as…
Q: Consider the variable X whose mean and variance are given respectively by Hx = 27.2 and Var(X) =8.…
A: GivenμX=27.2Var(X)=8
Q: Sophia who took the Graduate Record Examination (GRE) scored 160 on the Verbal Reasoning section and…
A: As per Bartleby guidelines, when more than 3 subparts are asked, only first 3 should be answered.…
Q: Use z scores to compare the given values. Based on sample data, newborn males have weights with a…
A: Answer: the given value are Based on sample data, newborn males have weights with a mean of μ =…
Q: Does where you live affect your insurance rate? The mean auto insurance rate for 29 drivers in a…
A: Level of significance ɑ=0.025, df=n1+n2-2
Q: For bone density scores that are normally distributed with a mean of 0 and a standard deviation of…
A: Given information Mean μ =0 Standard deviation ? = 1 a) Percentage of scores that are significantly…
Q: only part 4.
A: If the sample size increases from 8, then the standard deviation, σ decreases.
Q: Why roles are reserved for the variance and particularly for its square root, the standard…
A: Variance and standard deviation: Variance measures absolute variability in a data set, calculated…
Q: Assume thAt scores on a standardized test are known to follow a bell shaped distribution with a mean…
A: L
Q: Here is some data for two variables: "Number of Office Hours Visits" and "Score in the Class." The…
A: The proportion of variability in the variable "score" that can be explained (or attributable) by…
Q: A researcher performs a study on weekly per capita milk intake. A previous study found weekly per…
A: From the given information, let X be the weekly per capita milk intake. Here, X follows normal…
Q: The concentration of benzene was measured in units of milligrams per liter for a simple random…
A: Let, μ1 : the population mean benzene concentration for untreated water and μ2: the population…
Q: Two chemical companies can supply a raw material. The concentration of a particular element in this…
A: The population variance of concentration of the element by company 1 is σ12 and the population…
Q: The scores on the Accuplacer test and High School GPAs are normally distributed. The Accuplacer test…
A: Since There are two separate questions aksed, according to our guidelines we will answer only first…
Q: Jose's ACT score had a z-score of 1.15. What was his ACT score? Standardized tests: In a particular…
A:
Q: A standardized exam's scores are normally distributed. In a recent year, the mean test score was…
A:
Q: The sum of the squared deviation scores is SS = 20 for a sample of n = 6 scores. What is the…
A: The variance of the sample can be calculated as:
Q: Claim: The mean pulse rate (in beats per minute) of adult males is equal to 69 bpm. For a random…
A: The hypothesized mean μ=69 The sample size n=144 The sample mean x¯=69.5 The sample standard…
Q: st 15 years have shown that the average rainfall in a certain region of the country, for the month…
A: Given:n1=15n2=15x bar1=1.20x bar 2=1.35s1=0.45s2=0.54 The assumptions is of the normal populations…
Q: SAT scores are normally distributed with a mean of 1,800 and a variance of 22,500. Given arandom…
A:
Q: The mean of his total score is (Round to the nearest integer as needed.) The standard deviation of…
A: It is given that Mean, μ = 84 Standard deviation, σ = 8
Q: . b) The score of a student who scored worse than 80% of the test takers in the Verbal Reasoning…
A: Here, for the verbal part- Mean (μ)= 151 Standard deviation (δ) = 7 for the quantitative part- Mean…
Q: In a large section of a statistics class, the points for the final exam are normally distributed,…
A: Finding the lowest score that would qualify a student for an A grade:The points for the final exam…
Q: A standardized exam's scores are normally distributed. In a recent year, the mean test score was…
A:
Q: The frequency distribution was obtained using a class width of 0.5 for data on cigarette tax rates.…
A: Tax rate Freq(f) x xf x^2 x^2*f 0.00 - 0.49 7 0.245 1.715 0.060025 0.420175 0.5 - 0.99 12 0.745…
Q: The sample standard deviation for the Goodyear Silents' score is 5.55. (mean is 6) The sample…
A: Z=X¯-μσ=Z score μ=mean and σ= standard deviation
Q: State whether the following statements are true or false :
A: Here use some basic of measure
Q: Assume that you have been provided the following information for a sample of cars The covariance…
A: The covariance between weight and miles per gallon is equal to -4.0 pound-miles. The standard…
Q: Assume that you have been provided the following information for a sample of cars The covariance…
A: The two variables of interest are: "miles per gallon" and "weight".The sample covariance (as the…
2. Find the
3. In a large class, on exam 1, the mean and standard deviation of scores were 78 and 20, respectively, for exam 2, the mean and standard dervationwere 72 and 15, respectively. The
Trending now
This is a popular solution!
Step by step
Solved in 2 steps
- An analysis of variance produces SSb=35,SSw=15 and a F ratio with the df=1,5.What is the F ratio?X is a normal variable with mean of 8 and variance of 97. What is the z-score when x = 3?The concentration of benzene was measured in units of milligrams per liter for a simple random sample of five specimens of untreated wastewater produced at a gas field. The sample mean was 4.6 with a sample standard deviation of 2.7. Seven specimens of treated wastewater had an average benzene concentration of 7.9 with a standard deviation of 2.3. It is reasonable to assume that both samples come from populations that are approximately normal. Can you conclude that the mean benzene concentration differs between treated water and untreated water? Let h1 denote the mean benzene concentration for untreated water and h2 denote the mean benzene concentration for treated water. Use the a=0.05 level the p-value method with the TI-84 Plus calculator. please show p value!
- Suppose that for the past several decades, daily precipitation in Seattle, Washington has had a mean of 2.4 mm and a standard deviation of 11.4 mm. Researchers suspect that in recent years, the mean amount of daily precipitation has changed, so they plan to obtain data for a random sample of 195 days over the past five years and use this data to conduct a one-sample ?z‑test of ?0:?=2.4H0:μ=2.4 mm against ?1:?≠2.4H1:μ≠2.4 mm, where ?μ is the mean daily precipitation for the last five years. Although they realize that rainfall does not follow a normal distribution, they feel safe using a ?z‑test because the sample size is large. The researchers want to know what the power of this test is to reject the null hypothesis at significance level ?=0.05α=0.05 if the actual mean daily precipitation is 2.6 mm or more. Computing power by hand requires two steps. The first step is to use a significance level of 0.05 to determine the values of the sample mean for which they will reject their null…An ecologist is studying the impact of local polluted waters on the growth of alligators. The length of adult male alligators typically follows a normal distribution with a standard deviation of 2 feet. The ecologist wants to estimate the mean length of this population of alligators. Suppose she samples n alligators at random and uses the sample mean, X to as an estimator for u. a. What is the bias and variance of the estimator? (Note, these may be a function of n.) b. If n = 4, what is the probability that the estimator is within one foot of the true mean? (I.e. find P(|X – µ| < 1). c. What sample size, n, is required for the estimator to be within one foot of the true mean with 95% probability? (I.e. find the value of n that satisfies P(|X – µ| < 1) = 0.95.) d. Suppose the ecologist ends up sampling n = 9 alligators and calculates a sample mean of ī = 10.4 feet. Construct a 95% confidence interval for the population mean. e. Give an interpretation for the interval obtained in (d).A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1474 and the standard deviation was 319. The test scores of four students selected at random are 1880, 1190, 2210, and 1380. Find the z-scores that correspond to each value and determine whether any of the values are unusual. The Z-score for 1880 is (Round to two decimal places as needed.) The Z-score for 1190 is (Round to two decimal places as needed.) The z-score for 2210 is (Round to two decimal places as needed.) The z-score for 1380 is (Round to two decimal places as needed.) Which values, if any, are unusual? Select the correct choice below and, if necessary, fill in the answer box within your choice. OA. The unusual value(s) is/are (Use a comma to separate answers as needed.) RECH OB. None of the values are unusual.
- A physical therapist wanted to know whether the mean step pulse of men was less than the mean step pulse of women. She randomly selected 54 men and 70 women to participate in the study. Each subject was required to step up and down a 6-inch platform. The pulse of each subject was then recorded. The following results were obtained. Two sample T for Men vs Women N Mean StDev SE Mean Men Women 98% CI for mu Men - mu Women (- 12.20, - 1.00) T-Test mu Men = mu Women (vs H2 O C. Ho: H1 = H2; Ha: H1 #H2 (b) Identify the P-value and state the researcher's conclusion if the level of significance was a = 0.01. What is the P-value? P-value =A professor at a local community college noted that the grades of his students were normally distributed with a mean of 84 and a standard deviation of 6. The professor has informed us that 10 percent of his students received A's while only 2.5 percent of his students failed the course and received F's. a. To the nearest tenth, what is the minimum score needed to make an A? b. To the nearest tenth, what is the maximum score among those who received an F? c. If there were 4 students who did not pass the course, how many students took the course?Suppose the mean and variance of variable X are given respectively by μ = 36.2 and Var(X) =4.2. What is the average of the squared values of variable X?
- I have asked this question twice and both times it has been wrong. Answer given F=.82 and .77 both these are incorrect. A bakery is considering buying one of two gas ovens. The bakery requires that the temperature remain constant during a baking operation. A study was conducted to measure the variance in temperature of the ovens during the baking process. The variance in temperature before the thermostat restarted the flame for the Monarch oven was 3.3 for 22 measurements. The variance for the Kraft oven was 4 for 25 measurements. Does this information provide sufficient reason to conclude that there is a difference in the variances for the two ovens? Assume measurements are normally distributed and use a 0.02 level of significance.Assume that you have been provided the following information for a sample of cars The covariance between weight and miles per gallon is equal to -4.9 pound-miles. The standard deviation of the cars' mileages is 7.75. The standard deviation of the cars' weights is 0.94. Estimate the correlation coefficient to the first decimal place.A new Economic / Social Conservatism Scale has scores between 0 and 30 (0 being extreme liberal, 30 being extreme conservative). The mean score is 21 and standard deviation of scores is 5. You want to convert the original scale (call it X) to a new scale (call it Y) that has scores between 0 and 100. What is the correlation of X and Y?
