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Math Help - Complety lost on stastics problem!

  1. #1
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    Complety lost on stastics problem!

    No matter how I approach it..i don't get it!

    A recent study of 25 students reported that they spend an average of $18.53 per week on gas. The standard deviation of the sample was $3.00. Find the 95% confidence interval of the true mean.
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  2. #2
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    Quote Originally Posted by Mahoganybeauty06 View Post
    No matter how I approach it..i don't get it!

    A recent study of 25 students reported that they spend an average of $18.53 per week on gas. The standard deviation of the sample was $3.00. Find the 95% confidence interval of the true mean.
    The formula you need can be found here: Confidence Intervals

    The formula will also be in your class notes and textbook. Please show what you've tried and say where you get stuck.
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    Quote Originally Posted by Mahoganybeauty06 View Post
    No matter how I approach it..i don't get it!

    A recent study of 25 students reported that they spend an average of $18.53 per week on gas. The standard deviation of the sample was $3.00. Find the 95% confidence interval of the true mean.
    By the Central Limit Theorem

    Z=\displaystyle\huge\frac{\bar{X}-\mu}{\left(\frac{\sigma}{\sqrt{n}}\right)}

    where \sigma is the population SD, \mu is the population mean, n is the sample size,

    \bar{X} is the sample mean and \frac{\sigma}{\sqrt{n}} is the sample SD.

    The 95% interval ranges from 2.5% to 97.5%.

    Locate the Z-score for 97.5% and use the values given to rearrange the equation for \mu
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