A random sample of college students were surveyed about technological devices. They were asked, “How many cell phone chargers do you have in your household?” The table below represents the probability density function for the random variable X, the number of cell phone chargers per household. Find the standard deviation of X. Round the final answer to two decimal places. x P(X = x) 4 1/4 5 1/4 9 1/2

A random sample of college students were surveyed about technological devices. They were asked, “How many cell phone chargers do you have in your household?” The table below represents the probability density function for the random variable X, the number of cell phone chargers per household. Find the standard deviation of X. Round the final answer to two decimal places. x P(X = x) 4 1/4 5 1/4 9 1/2

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

See similar textbooks

Similar questions

Gentle Ben is a Morgan horse at a Colorado dude ranch. Over the past 8 weeks, a veterinarian took the following glucose readings from this horse (in mg/100 ml). 91 86 80 107 99 108 86 89 The sample mean is x ≈ 93.3. Let x be a random variable representing glucose readings taken from Gentle Ben. We may assume that x has a normal distribution, and we know from past experience that ? = 12.5. The mean glucose level for horses should be ? = 85 mg/100 ml.† Do these data indicate that Gentle Ben has an overall average glucose level higher than 85? Use ? = 0.05. (a) What is the level of significance? b. (b) What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. The Student's t, since we assume that x has a normal distribution with known ?.The Student's t, since n is large with unknown ?. The standard normal, since we assume that x has a normal distribution with unknown ?.The standard normal, since we assume that x has a normal…
Assume that the probability of a being born with Genetic Condition B is p=1/5. A study looks at a random sample of 971 volunteers.Find the most likely number of the 971 volunteers to have Genetic Condition B.(Round answer to one decimal place.)μ = Let X represent the number of volunteers (out of 971) who have Genetic Condition B. Find the standard deviation for the probability distribution of X.(Round answer to two decimal places.)σ = Use the range rule of thumb to find the minimum usual value μ–2σ and the maximum usual value μ+2σ.Enter answer as an interval using square-brackets only with whole numbers.usual values =
Gentle Ben is a Morgan horse at a Colorado dude ranch. Over the past 8 weeks, a veterinarian took the following glucose readings from this horse (in mg/100 ml). 91 88 82 103 97 108 84 91 The sample mean is x ≈ 93.0. Let x be a random variable representing glucose readings taken from Gentle Ben. We may assume that x has a normal distribution, and we know from past experience that ? = 12.5. The mean glucose level for horses should be ? = 85 mg/100 ml.† Do these data indicate that Gentle Ben has an overall average glucose level higher than 85? Use ? = 0.05. (a) What is the level of significance? State the null and alternate hypotheses. Will you use a left-tailed, right-tailed, or two-tailed test? H0: ? = 85; H1: ? > 85; right-tailed H0: ? > 85; H1: ? = 85; right-tailed H0: ? = 85; H1: ? ≠ 85; two-tailed H0: ? = 85; H1: ? < 85; left-tailed (b) What sampling distribution will you use? Explain the rationale for your choice of sampling distribution.…
Assume that the probability of a being born with Genetic Condition B is p = 7/60. A study looks at a random sample of 826 volunteers. Find the most likely number of the 826 volunteers to have Genetic Condition B. (Round answer to one decimal place.) H = Let X represent the number of volunteers (out of 826) who have Genetic Condition B. Find the standard deviation for the probability distribution of X. (Round answer to two ecimal places.) 0 = Use the range rule of thumb to find the minimum usual value µ-20 and the maximum usual value μ+2o. Enter answer as an interval using square-brackets only with whole numbers. usual values =
Assume that the probability of a being born with Genetic Condition B is p = 11/60. A study looks at a random sample of 1384 volunteers. Find the most likely number of the 1384 volunteers to have Genetic Condition B. (Round answer to one decimal place.) μ = Let X represent the number of volunteers (out of 1384) who have Genetic Condition B. Find the standard deviation for the probability distribution of X. (Round answer to two decimal places.) 0 = Use the range rule of thumb to find the minimum usual value µ-20 and the maximum usual value μ+20. Enter answer as an interval using square-brackets only with whole numbers. usual values=
Gentle Ben is a Morgan horse at a Colorado dude ranch. Over the past 8 weeks, a veterinarian took the following glucose readings from this horse (in mg/100 ml). 94 87 83 104 98 108 84 89 The sample mean is x = 93.4. Let x be a random variable representing glucose readings taken from Gentle Ben. We may assume that x has a normal distribution, and we know from past experience that o = 12.5. The mean glucose level for horses should be u = 85 mg/100 ml.t Do these data indicate that Gentle Ben has an overall average glucose level higher than 85? Use a = 0.05. (a) What is the level of significance? State the null and alternate hypotheses. Will you use a left-tailed, right-tailed, or two-tailed test? O Ho: H = 85; H,: u + 85; two-tailed O Ho: H = 85; H: µ > 85; right-tailed O Ho: H > 85; H,: µ = 85; right-tailed O Ho: H = 85; H,: µ < 85; left-tailed (b) What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. O The Student's t, since we assume…
Find the indicated probability and interpret the result. From 1975 through 2020, the mean annual gain of the Dow Jones Industrial Average was 653. A random sample of 33 years is selected from this population. What is the probability that the mean gain for the sample was between 400 and 800? Assume σ = 1540. The probability is ☐ (Round to four decimal places as needed.)
Gentle Ben is a Morgan horse at a Colorado dude ranch. Over the past 8 weeks, a veterinarian took the following glucose readings from this horse (in mg/100 ml). 91 88 80 103 97 110 86 89 The sample mean is x ≈ 93.0. Let x be a random variable representing glucose readings taken from Gentle Ben. We may assume that x has a normal distribution, and we know from past experience that ? = 12.5. The mean glucose level for horses should be ? = 85 mg/100 ml.† Do these data indicate that Gentle Ben has an overall average glucose level higher than 85? Use ? = 0.05. (a)What is the level of significance? State the null and alternate hypotheses. Will you use a left-tailed, right-tailed, or two-tailed test? H0: ? > 85; H1: ? = 85; right-tailed H0: ? = 85; H1: ? < 85; left-tailed H0: ? = 85; H1: ? ≠ 85; two-tailed H0: ? = 85; H1: ? > 85; right-tailed (b)What sampling distribution will you use? Explain the rationale for your choice of sampling distribution. The…
Let X be the number of workouts a person does in a week. Suppose that X has the following probability distribution: 3 e d C # $ SB 4 C A. What is the expected number of workouts a person Standard deviation = r Expected value B. What is the standard deviation of the number of workouts a person f V You can use the tool below to help you compute standard deviation. % 5 t ca b 6 X 0 P p| 0.09 Oll y h hop & 7 n 1 2 3 0.14 0.43 | 0.25 O u does per Round to 2 decimal places, as needed. does per week? j Round to 2 decimal places, as needed. * 00 week? 8 4 0.09 3 k ( 9 O < alt O р ctrl [ ? + 11 = 1 < backs 1
Assume you have a normal distribution representing the likelihood of project completion times. The mean of this distribution is 14, and the standard deviation is 4. The probability of completing the project in 15 or fewer days is: a. 0.59 b. 0.27 c. 0.93 d. 0.75
The following table shows the results of a medical test. Positive Test Result Negative Test Result 95.3 4.6 Total 82.6 % 4.6 Has Disease X % 491 24 % 515 Does Not Have Disease 45 Use the preceding data to estimate each of the following. (Express each response as a percentage rounded to one decimal place.) a. If a person has the disease, what is the probability that person tests positive? This is the sensitivity or true positive rate of a test. 214 259 Total b. If a person has the disease, what is the probability that person tests negative? This is sometimes called the false negative rate. 536 238 774 c. If a person does not have the disease, what is the probability that person tests negative? This is the specificity or true negative rate of a test. d. If a person does not have the disease, what is the probability that person tests positive? This is sometimes called the false positive rate. X %
Calculate the standard deviation ? of X for the probability distribution. (Round your answer to two decimal places.) x −5 −1 0 2 5 10 P(X = x) 0.1 0.2 0.3 0.1 0.3 0 ? =