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# Standard Error

### Standard Deviation and Mean ? - The mean time to perform a certain task in Kindergarten follows a mound shaped distribution. The mean time is 10 minutes with a standard deviation of 1 minute. The teachers want to establish a time such that approximately only 2.5% will take longer than this time. ...

The mean time to perform a certain task in Kindergarten follows a mound shaped distribution. The mean time is 10 minutes with a standard deviation of 1 minute. The teachers want to establish a time such that approximately only 2.5% will take longer than this time. A. The time is 8 minutes. B. The time is 9 min

### Standard error of the difference between means ...

Group 1 m=30.000 s=2.100 n=14 group 2 m=25.000 s=1.900 n=15 What is the value of the standard error of the difference between means and the observed value of t.

### Mean, Standard Error - a) The mean=25 and the standard error=8. If samples of size n=16 are selected, can we say anything about the(x-bar)distribution of sample means? and if the original x distribution is normal, can we say anything about the (x-bar) distribution of random samples of size 16? Find p(68<=x-bar<=73).

A) The mean=25 and the standard error=8. If samples of size n=16 are selected, can we say anything about the(x-bar)distribution of sample means? and if the original x distribution is normal, can we say anything about the (x-bar) distribution of random samples of size 16? Find p(68<=x-bar<=73).

### Sampling distribution of sample mean.

An accounting firm is planning for the next tax preparation season. From last year's returns, the firm collects a systematic random sample of 100 filings. The 100 filings showed an average preparation time of 90 minutes with a standard deviation of 140 minutes. What is the standard error of the mean? a.14 minutes b. 140 mi

### Statistics: Sampling Error and Sample Size

A produce manager wants to estimate the mean size of coke bottle fills with 95 percent confidence. A preliminary sample of 12 bottles shows a sample standard deviation of 3 mil, and mean of 500. (A) What is the sampling or testing error? (B) What would be the sample size to reduce the erro

### Standard Error of Mean

True or False: (please show me why) A simple random sample of 100 observations was taken from a large population and the sample mean and the standard deviation were determined to be 80 and 12 respectively. The standard error of the mean is 0.12.

### Distribution of Emergency Calls to Detroit

Emergency calls to Detroit, Michigan 911 system, for the past 24 weeks are as follows week - calls week - calls week - calls 1 50 9 35 17 55 2 35 10 20 18 40 3 25 11 15 19 35 4 40 12 40 20 60 5 4

### standard error of the proportions of minority students

A study at a college on the west coast reveals that, historically 45% of their students are minority students. If random samples of size of 75 is selected, the standard error of the proportions of student in the sample, who are minority students is

### Computing an exponentially smoothing forecast

The manager of the BP Service Station wants to forecast the demand for unleaded gasoline next month so that the proper number of gallons can be ordered from the distributor. The owner has accumulated the following data on demand for unleaded gasoline from sales during the past 10 months. Month Gasoline Demand

### Multiple Choice - Assume that a procedure yields a binomial distribution with a trial repeated n times.

Assume that a procedure yields a binomial distribution with a trial repeated n times. Use the binomial probability formula to find the probability of x successes given the probability p of success on a single trial:n = 6, x = 2, p = 0.45. 0.278 0.208 0.003 0.057 Use the Poisson distribution to fi

### Sample Mean and Standard Error

According to an IRS study, it takes an average of 330 minutes for taxpayers... 18. According to an IRS study, it takes an average of 330 minutes for taxpayers to prepare, copy, and electronically file a 1040 tax form. A consumer watchdog agency selects a random sample of 40 taxpayers and finds the standard deviation of the ti

### Standard error of the sample mean

If the population standard deviation for normally distributed standardized test achievement is known to be 7.20, what would the standard error of the sample mean be if we were to draw a random sample of 16 scores?

### Referring to the table what is the standard error of the estimate, Syx, for data?

A candy bar manufacturer is interested in trying to estimate how sales are influenced by the price of their product. To do this the company randomly chooses 6 small cities and offers the candy bar at different prices. Using candy bar sales as the dependent variable, the company will conduct a simple linear regression on the data

### Regression and Standard Error

(See attached file for full problem description with diagrams and all details) --- Mr. James McWhinney, president of Daniel-James Financial Services, believes there is a relationship between the number of client contacts and the dollar amount of sales. To document this assertion, Mr. McWhinney gathered the following sample inf

### Finding Standard error and probabilities of samples

Information from the American Institute of Insurance indicates the mean amount of life insurance per household in the United States is \$110,000. This distribution is positively skewed. The standard deviation of the population is not known. a. A random sample of 50 households revealed a mean of \$112,000 and a standard deviatio

### Statistics: Various Problems

For questions 1, 3 and 4, please refer to the attached document for numerical information. 1. Mr. James McWhinney, president of Daniel-James Financial Services, believes there is a relationship between the number of client contacts and the dollar amount of sales. To document this assertion, Mr. McWhinney gathered the attache

### Sampling Error when Estimating a Population Proportion

Assume the following data represents a population of 50 values. Values equal to 1 indicate that a particular attribute is present, a value equal to 0 indicates the attribute is not present. 1......1......1......1......1......1......1......1......0......0 0......1......1......0......0......1......1......1......0......1 0......

### expected value, standard errors of the mean (probability)

N=36 stand. dev. is 3 mean = 5 What is the expected value? What is the probability that the sample mean will be at least 4? What is the probability that the sample mean will be at least 5.90?

### Statistics question

Please give a full explanation of the difference between a standard error of the mean and a standard error of the difference between means.

### Naive Forecasting

Naive Forecasting Complete the table, then determine the MAD and MSE. What is your forecast for Week 13? (Some of the values have been filled in for you to help with your calculations.) McCray Enterprise: Weekly closing price per share Week Price Forecast

### Standard Error and Measurement

If the raw score on a test is 75 and the Standard Error and Measurement (SEM) is 5, what is the range of scores 2 standard errors out?