# normal distribution

1. ### Normal Distribution times constant

I can't seem to find anything about this on the web. If I have a random variable distributed Normally: x ~ Normal(mean,variance) is the distribution of the random variable still normal if I multiply it by a constant, and if so, how does it affect the mean and variance?
2. ### A question about the distribution of random numbers

Suppose I have two independent random variables A, and B, which are distributed Normally as follows: A: N~(MA,VA) B: N~(MB,VB) Now consider that I draw many A's and B's and arrange these randomly and pair-wise (A's next to B's). Having done that, I then identify all those values of A...
3. ### Normal Distribution and Grade Cut-offs

Hello, I tried googling this question, watching how-to videos, and read over the chapter in my textbook several times but I cannot seem to understand how to go about solving this question. The following question applies to a normal distribution of statistics test scores with a mean of 100...
4. ### Quick SPSS testing question

Hi, I have a data set with two questions: - whether one visits coffee chains or independent coffee stores - results are set within 1 (chains) and 2 (independent) --- (for which I have 106 for chains and 24 for independents equalling a total of 130 responses) - whether these locations have a...
5. ### Normal distribution, Z-Score and Probability Help.

I'm having a difficult time trying to answer these questions. Any help would be very helpful. The time it takes a randomly selected job applicant to perform a certain task has a normal distribution with mean 120 seconds and standard deviation 12 seconds. 1. We are interested in computing...
6. ### What is the role of the test statistic? [I'm not talking about the p-value]

For example when Shapiro-Wilk test shows the statistic .945, df=12, p-value=.563 I know it's 'not significant' and I retain the H0 hypothesis, but I also have to write about the test statistic (.945), so what does it mean, when is it high, when is it low, comparing to what? Regards, Chris
7. ### distribution

Distribute six energy units to four different states, 0ε, 1ε, 2ε, 3ε, with the constraint that the total energy of the system is equal to 4ε which must determine the weight and n(ε) for each energy level.
8. ### 95% Intervals

I'm new here (and relatively new to statistics) so I apologize if this thread is in the wrong place. I have a problem that seems relatively easy but it has me stumped... I need help with intervals on data. I thought tolerance intervals would work but they are not giving me what I want...
9. ### Normal Distribution Question Approach

Hello everyone, first of all, this has nothing to do with coursework's or homework, I'm currently revising for an exam, so please help me. Following question: Grade point averages of students on a large campus follow a normal distribution with a mean 2.6 and a standard deviation of 0.5...
10. ### Two tailed t-test for data sets that do not follow normal distribution?

Hi there, I'm doing some work comparing two sets of people: those I invited to an event, and those who actually showed up. I am comparing the amount of money they donated to our charity in the past. I have the amounts bucketed into about five categories (i.e., $100-$199, $200-$299, etc.)...
11. ### lognormal process time, output rate distribution

For a project of factory lay out we have given an assembly time of 20 min and stdev of 5 min. distribution type is not given but assumed lognormal (since normal is infeasable because of the possibility of negative assembly times). At what rate do the products exit the assembly station?for...
12. ### How to find sample variance given population mean and variance (no specific data)

Hi, I am working on the following problem:confused:: Population Mean = 1000 Population Std. Dev. = 400 Sample N=25 How many, from the sample of 25, are greater than 1000 if the sample mean is 1100. Can I assume the sample std. dev. is the same as the population? Does anyone know...
13. ### Sample size - chi-squared vs. normal

Hi, I apologise if this is the wrong thread. I need to calculate sample sizes, but I'm curious as to why the commonly used Krejcie-Morgan tables use a chi-squared formula rather than a student-t or a normal distribution. I see quite a few other papers that use the latter distributions...
14. ### Finding IRQ from standard deviation and normal distribution

Here's my problem. Any help or insight would be greatly appreciated: A report provided a standard deviation on waiting time to single room occupancy hotels to be 12.9 days. Given that the waiting times follow a Normal distribution, what is the IQR here (single number)? Thanks in advance!!
15. ### the third statistics independent with sample mean and variance

As we know, if X1, X2 ... XN are IID normal distribution, then the mean of the samples and the variance of the samples are independent. My question is, could we use X1, X2 ... XN to construct the third statistics, which independent with the sample mean and variance.