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Normal Distribution

Stepwise significance testing format

The most important material reclaimed from beverage bottles is PET plastic. A serious impurity is aluminum, which later can clog the filters in extruders when the recycled material is used. The following are the amounts (in ppm by weight of aluminum) found in bihourly samples of PET recovered at the plant over roughly a two day

Binomial pdf

The number of days per year that it snows in an eastern Idaho town is normally distributed with a mean of 25 days and a standard deviation of 5.4 days. 1. What is the chance that it snows exactly 25 days?

Find percentiles from a given normal distribution

Your firm is attempting to reduce its cost of maintenance of customers by culling the least-productive of them. A census of sales records was undertaken and it was determined that the mean level of sale of all customers was $235,000 with a standard deviation of $15,000. (a) It is your desire to eliminate from your customer po


6.38 Obtain the z-score that has an area of .95 to its right. 6.40 Find the following z-scores a. z0.03 b. z0.005

Normal distribution

6.12 a. The area under the standard normal curve with parameters m = 64.4 and o= 2.4 that lies to the left of 61 is 0.0783. Use this information to estimate the percentage of female's students who are shorter than 61 inches. 6.14 According to the National Health and Nutrition Examination Survey, the serum (noncellular portio

Using Excel to make plots of Gaussian distribution

I am using Analytical Chemistry 7th edition By Skoog, West, Holler, and Crouch. please let me know if any additional info. is needed. There is a sample of the graph in the book Chapter 6 and 7. Using Excel, construct a spreadsheet to make two plots of a Gaussian distribution: 1. relative frequency vs deviation from the mean

Basic Statistics Problem (Normal Distribution; Mean; Standard Deviation)

I am having trouble with PART B of this problem. Here is the whole problem: Assume body temperatures are normally distributed with mean of 98.2 and a standard dev. of 0.62 Part A) Assuming a hospital defines a fever as 100 or over, determine the percentage of a normal healthy person considered to have a fever using Z tabl


Question 1 If a normal distribution of empirical scores is converted to a distribution of z scores: A. The new mean will be zero B. The new standard deviation will be one C. Both A and B D. Neither A and B. Question 2 Milquetoasts gracious statistics professor at Northwestern announced that he would drop th

Uniform distribution

1. X_1,X_2,...,X_n are independent and uniformly distributed on [0,1] a. standardize X_1+X_2+...+x_n b. Give mgf of THE STANDARDIZED (a) sum. 2. Suppose X is normal with mean u and variance sigma^2. P{u<= X <= u + 1.5 sigma}

Find the Critical Values and Determine the Appropriate Distribution

Do one of the following as appropriate: a) Find the critical value t (alpha/2) b) Find the critical value z (alpha/2) c) State that neither the normal nor the t distribution applies. Problem: 95%; n= 40; sigma is unknown; population appears to be skewed. (See attachment for complete question and symbols that did not come


How do I know which distribution to use for the following and when/where do tables apply?: Nonstandard Normal Binomial Normal Standard normal Central limit theorem a) Mean is 0, stand. dev. is 0 degrees C., find P between 0.05 and 1.50 b)Mean is 63.6 and s.d. is 2.5; Club had requirement that women must be 70 inch

Intro Stats New (multi choice)

A. n=17. Find P(t<-1.746) aa) .05 bb).95 cc).45 dd) 1.0 B. A random sample of 64 observations is observed from a population of SAT scores in 2001. Which of the following is a correct statement? aa) It is the distribution of the observed 64 SAT scores. bb) X-bar is approximately normal. cc) The mean of all possible x-bars is ave

Normal Distrubution

An airline wants to find out how long it takes for a travel agent to complete an airline ticket order from a computer terminal. Assume that the mean transaction time is 150 seconds. also assume that the population of transaction times has normal frequency curve. Find the probability that the 150 and 175 seconds to complete if s

Only for 103997

Only for above listed OTA. Last one for this semester. Thank you. Hope you're around mid- June through July. Have a great summer! Problem: In a stan. normal distribution, find the z-score that separates the top 20% area from the bottom 80%.

Only for OTA 103997

Only for above listed OTA Body Temperatures normally distributed with a mean of 98.2 and a stan. dev. of 0.62. if 100 people randomly selected find probablity their mean body temperature is between 98.15 and 98.5 degrees.

Only for OTA 103997, 103300, or 103866

Only for above listed OTA's Assume thermometer readings are normally distributed with a mean of 0 degree and a Standard deviant of 1.00 degree F. Find indicated probability where z is reading in degrees. P(z<1.645)

Estimated percentile rank

Tthe mean for a special distribution is 100 and the standard deviation is 15. What is the estimated percentile for an individual who had a score of 90 on this scale?

Questions from Textbook: Statistics for Management (7th Ed. ) Levin & Rubin

1). In a normal distribution with a standard deviation of 5.0, the probability that an observation selected at random exceeds 21 is 0.14 (14%). a). Find the mean of the distribution. b). Find the value of below which 4 percent of the values in the distribution lie. 2). The company's manager calculates that it requires

What percentage of this model radio will last longer than 9.5 years?

1) What percentage of this model radio will last longer than 9.5 years? 2) Suppose the manufacturer guarantees the radio for 8 years. What percentage of radios will have to be replaced? 3) Suppose the manufacturer is willing to replace only 2% of this model radio. What should be the length of the guarantee?

Normally dist with mean and SD

Nurses saleries are Normally distributed with mean of 35,000 and standard deviation$1700. A. What is the probability that a nurse earn more than $36,000? B. What is the probality that a group of 10 nurses have mean salary greater than $36,000? c. What salary does a nurse need to earn to have a salary in the top 25% of nurses'

Confidence Limits

A pollster conducted a survy of voters' opinions on a local school bond issue. What would the 95 percent confidence limits be if 53 percent of 1000 people sampled were in favor of the school bond issue? What would the 99 percent confidence limits be for the same sample? I have SPSS 11.0 here. Can I enter this info into it and

3584- distribution P(z<, = or >z)

I need some serious explanation. I cannot even understand what to study for the frist 6 questions on the test about the formula I posted in this subject line. The book I am using is Elementary Statistics by mario F. Triola. 8th edition. Here is what I am to study: Students will have 2 hours to answer 20 exam questions.

Show that for all &#961; and v...

1. (a) Show that if Z1 and Z2 are independent standard normal random variables, then for all &#961; (correlation), Z1 and &#961;Z1+sqrt(1-&#961;2)*Z2 are standard normal with correlation &#961;. (b) Show that for all &#961; and v, T1 = (Z1)/sqrt(X/v)and T2 = (Z2)/sqrt(X/v) have correlation &#961;, where Z1and Z2 are standa

Normal Distribution problem

The amounts dispensed by a cola machine follow the normal distribution with a mean of 7 ounces and a standard deviation of 0.10 ounces per cup. How much cola is dispensed in the largest 1 percent of the cups?

Hypothesis in statistics

A light bulb manufacturer advertises that the average life for their light bulbs is 800 hours. A random sample of 15 of their light bulbs resulted in the following data, in hours; 990 841 953 612 727 800 686 594 835 897 943 791 750 667 723 Assume that the bulb life is normally distributed. At the 10% significance level, do

Estimation using Normal Distribution

A random sample of 55 adults in a certain country showed an average height of six feet (72 inches) for adults. Statistics show the population standard deviation to be 3.40 inches. Calculate the 95% confidence interval for the mean height of the adult population.

What inventory levels to carry? Simulation? Optimization?

We are asked (ideally) to use Crystal Ball (CB), an Excel add-in, or Excel itself to do this inventory problem. CB would be ideal, but we can use just plain-old Excel if it can do what needs to be done. I see this as a simulation or maybe optimization problem, but not sure how to tackle it. Given historical data on deman

Probability Distributions: Normal Distribution

It is known that the IQ scores of workers in a certain company are normally distributed with a standard deviation of ten. If 0.13% of the workers have IQ's in excess of 130 calculate the mean IQ.