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Probability

Z-score of sample means

Compute a z statistic for each, assuming the population has a mean of 100 and a standard deviation of 20: Formula is z = (x - μ) / σ a. sample of 43 scores has a mean of 101: - 2.9 b. sample of 60 scores has a mean of 96: - 1.8 c. sample of 29 scores has a mean of 100: -3.55

Null and Alternative Hypotheses and Type I and II Errors

Share the null and alternative hypotheses for a decision that is relevant to your life. This can be a personal item or something at work. Be sure that it is mathematical in nature. Additionally, identify the Type I and Type II Errors that could occur with your decision‐making process. Be sure to quantify your hypotheses as mu

Computing Probability and Deciding Extreme Samples

Please explain how to solve. I have attempted to answer, please let me know if I'm right or wrong. Thank you! a random sample of n=9 scores is selected from a normal distribution with u= 80 and o=12. what is the probability that the sample mean will be between 76 and 84? * 0.9974 *0.3830 * 0.2586 * 0.6426 ( is this correc

Sample Mean and Population Mean: Standard Deviation

Please explain how to set up and solve. I have attempted to answer, please let me know if right or wrong... A sample of n= 36 scores is selected form a population with o= 12. if the sample mean of M=56 produces a z score of z= +3.00 then what is the population mean? * 56 *52 (is this correct?) * 54 *50 A sample of n=

SD and SE Questions

For a particular population, a sample of n=4 scores has a standard deviation error of 6. for the same population a sample of n=16 scores have a standard error of *3 * 8 *2 *6 A sample of n=16 scores has a standard deviation of 4. what is the standard deviation of the population from which the sample is obtained. * 64

Expected value of sample mean

A sample of n=100 scores is selected from a population with u= 80 with o= 20. on average how much error is expected between the sample mean and the population mean? * 0.8 points * 4 points * 0.2 points * 2 points If random samples, each with n=4 scores, are selected from a normal population with u= 80 and o=36, what i

Means, standard errors, expected values

For a population with u=80 and o=20, the distribution of sample means based on n=16 will have expected value of _____ and a standard error of ____. * 80; 1.25 (this is the one i had chosen at 1st?) * 80; 5 * 5; 80 * 20; 20 Samples of n=16 scores are selected from a population. If the distribution of sample means has an e

Tattoos and Attractiveness

There is some evidence indicating that people with visible tattoos are viewed more negatively than people without visible tattoos. In a similar study a researcher first obtains overall ratings of attractiveness for a woman with no tattoos shown in a color photo. On a 7 point scale the woman receives an average rating of u= 4.9,

Hypothesis Testing for One Sample Z Test

There is a popular belief that herbal remedies such as ginkgo biloba and ginseng may improve learning and memory in healthy adults, these effects are usually not supported by well controlled research. in a typical study a researcher obtains a sample of n=16 participants and has each person take a herbal supplement for 90 days. a

Sample Mean - Typical or Extreme Value

Please explain how to solve this simple steps. I'm having such a hard time getting this stuff! A normal distribution has a mean of u=60 and a standard deviation of o=18. For each of the following samples, compute the z scores for the sample mean, and determine whether the sample mean is a typical, representative value or an ext

Z-score calculation in simple steps

Please explain how to solve this. In simple steps please. A population with a mean of u=80 and a standard deviation of o=12 find the z-score corresponding to each of the following samples. M= 83 for a sample of n= 4 scores z=___ M= 83 for a sample and n= 16 scores z=___ M= 83 for a sample and n= 36 scores z=____

Standard Error calculations for population

A population has a standard deviation of o=20, how large a sample is necessary to have a standard error that is: Less than or equal to 5 points? n>______ Less than or equal to 2 points? n>______ Less than or equal to 1 point? n>______ If I have a sample of n=25 scores, what is the value of the population standard devi

Descriptive Statistics, Confidence Interval & Testing

Bottling Company Case Study /Calculate measurements of central tendency and dispersal. Determine confidence intervals for data. Imagine you are a manager at a major bottling company. Customers have begun to complain that the bottles of the brand of soda produced in your company contain less than the advertised sixteen (16)

Probability: expected value using exponential distribution

Please assist in answering the following question. Please submit details of work including excel sheet used to arrive to the solution. Provide interpretation of results and describe conclusions. 1. Suppose that a car rental agency offers insurance for a week that will cost $10 per day. A minor fender bender will cost $1,500,

investment science questions

9. There are two propositions: (a) I flip a coin, If it is heads, you are paid $3; if it is tails, you are paid $0. It costs you $1 to participate in this proposition. You may do so at any level, or repeatedly, and the payoffs scale accordingly. (b) You may keep your money in your pocket (earning no interest). Here is a third pr

Conditional Probabilities and Malaria

A medical test for malaria is subject to some error. Given a person who has malaria, the probability that the test will fail to reveal the malaria is 0.06. Given a person who does not have malaria, the test will correctly identify that the person does not have malaria with probability 0.91. In a particular area, 20% of the

Probability and Statistics Questions

1. A large shipment of computer chips is known to contain 8% defective chips. Suppose you select 500 chips at random. (a) What distribution does the number of defective chips in the sample of 500 satisfy? (Please characterize its relevant parameters.) (b) Suppose that you wish to calculate the probability that the numb

Expected Number of Lives Saved by the Defibrillator

Suppose that over the next several years, there will be 100 cardiac incidents at Silver's. Without a defibrillator, 30 victims will die before paramedics arrive. With a defibrillator, there is an 80% probability of saving a victim who would die without it. However, there is a 3% probability that improper use of the defibrilla

Confidence Interval & Hypothesis Testing: Cure Rate

A standard surgery was performed on 50 patients with severe sinus infection, and 36 were cured. a) Find a 95% confidence interval for the population cure rate or proportion. =0.5955, 0.8445 b) Do these data indicate that the population cure rate or proportion is more than 70%? Do a hypothesis test. Use alpha=0.05. z=0.30

Normal Probabilities with Z-Score

I need some help figuring this question out: Let x be a random variable that represents the speed of the first vehicle passing an observation point between 11am to 12n on a remote highway, automatically recorded by a police radar. Based on past recording over many days, the random variable has an approximate normal distributio

Conditional Probability and Fisher's Exact Test

I need some help answering this conditional probability question: The following table is based on a random sample of 100 employee in a large fortune 500 company # of days a week one exercises 2 or fewer days 18 (Male) 12 (Female) 3 or more d

Probability Questions

Looking for assistance to make sure I am calculation answers correctly for the following 2 scenarios. Please provide the answer and any formulas in excel spreadsheet. A standard deck of playing cards consists of fifty-two cards. The cards in each deck consist of four suits, namely spades (♠), clubs (♣), diamonds (♦)

Statistics: Finding Confidence Intervals

Using the spread sheet that is attached, develop 95% and 99% confidence intervals for the following: The mean hours per week that individuals spend in their vehicles,the average number of miles driven per week, the proportion of individuals who are satisfied with their vehicle and the proportion of individuals who have at least

Calculation of Normal and Binomial Probabilites

Question 1: A railway company operates a number of different services. One of these connects two cities and the journey time is assumed to be normally distributed with a mean of 125 minutes and a standard deviation of 5 minutes. The company operates a scheme where it refunds 25% of the fare paid if the journey takes longer t

Ethical issues on advertising the lottery

Do you think the state has any intention of ever stopping the lottery, given the fact that the state relies on it to bring millions of dollars into its treasury? Is it possible that lottery can make everyone a millionaire? Is it ethical to suggest that the purpose of the lottery is to make everyone a millionaire? FORMAT I. I

Events Relations in Statistics

1. According to an Ipsos poll, the perception of unfairness in the U.S. tax code is spread fairly evenly across income groups, age groups, and education levels. In an April 2006 survey of 1,005 adults, Ipsos reported that almost 60% of all people said the code is unfair, whereas slightly more than 60% of those making more than $

Z scores, Z statistics, p-value and APA format

Given the research scenario, data points, set of population parameters and alpha set at p = .05, generate the correct: - Pair of hypotheses for each data point - A z statistic and p value for each data point - Decision about the null hypothesis for each data point - APA-formatted statement of results for each data point

Probability for population proportion

In an online survey of 4,001 respondents, 8% were classified as productivity enhancers who are comfortable with technology and use the Internet for its practical value (data extracted from M. Himowitz, "How to Tell What Kind of Tech User You Are," Newsday, May 27, 2007, p F6). Suppose you select a sample of 400 students at your

Computing probability for normally distributed data

The U.S. Census Bureau announced that the median sales price of new houses sold in April 2008 was $221,600, and the mean sales price was $274,300 (www.census.gov/newhomesales, July 20, 2009). Assume that the standard deviation of the prices is $90,000.