Fairly basic statistics help

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Plugging in the values, we get:c = 1.96 * 3.71 = 7.27.Therefore, in summary, the value of c for which P(E(X) - c < X < E(X) + c) = 0.95 is 7.27 pounds.
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cameuth
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Homework Statement


Suppose that the weights of airline passenger bags are normally distributed with a mean of 48.14 pounds and a standard deviation of 3.71 pounds.
Let X represent the weight of a randomly selected bag. For what value of c is P(E(X) - c < X < E(X) + c)=0.95? Give your answer to four decimal places.

Homework Equations



I have statcrunch and a normal, poisson, and gamma calculator.

The Attempt at a Solution



For this I assume we are looking for a standard deviation. I've been playing with a calculator but honestly I just need help getting started. thanks.
 
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  • #2
I think the best way to approach this problem is to visual what the problem is asking for. What is the region under the Normal Curve that it wants?

In this case, the symmetry could be of use to you.
 
  • #3
You're looking at a confidence interval.

The formula for it is: ##c = z^* \times \sigma##.
where z* is the critical z-value for the confidence level and ##\sigma## is the standard deviation.

For a confidence level of 0.95, z*=1.96, which you can find in any table for a standard normal distribution.
 

1. What is the purpose of conducting statistical analysis?

Statistical analysis is used to summarize and interpret data in a meaningful way. It allows researchers to make conclusions and predictions based on the data collected.

2. What are the basic concepts of statistics?

The basic concepts of statistics include measures of central tendency (mean, median, and mode), measures of variability (range, variance, and standard deviation), and probability.

3. How do I choose the appropriate statistical test for my data?

The choice of statistical test depends on the type of data you have and the research question you are trying to answer. It is important to consider the level of measurement, distribution of data, and the number of variables being compared.

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Descriptive statistics is used to summarize and describe a set of data, while inferential statistics is used to make predictions or generalizations about a larger population based on a sample of data.

5. How do I interpret the results of a statistical analysis?

The interpretation of statistical results depends on the specific test being used and the research question being addressed. It is important to consider the confidence interval, p-value, and effect size when interpreting the results.

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