A researcher conducted an Internet survey of 500 students at a particular college to estimate the average amount of money students spend on groceries per week. The data are normally distributed, with the highest weekly amount being $200 and the lowest weekly amount being $75. The sample mean is $140. What is the margin of error (ME), rounded to the nearest hundredth, for this college?

Respuesta :

Answer:

The margin of error is  [tex]ME = 2.2962[/tex]

Step-by-step explanation:

From the question we are told that

     The number of student is [tex]n = 500[/tex]

     The highest amount is  [tex]A =[/tex]$200

     The lowest amount is  [tex]B =[/tex] $75

       The sample mean is  [tex]x =[/tex] &140

The Standard deviation  of this set is mathematically evaluated as

            [tex]s = \frac{A-B}{4}[/tex]

Substituting values

            [tex]s = \frac{200-75}{4}[/tex]

            [tex]s = 31.25[/tex]

The margin of error (ME) is mathematically evaluated as

            [tex]ME = t_{n-1}__{\alpha }} * \frac{s}{\sqrt{n} }[/tex]

Where  [tex]t_{n-1}__{\alpha }}[/tex] is the critical value for [tex]\alpha = 0.05[/tex] i.e the significance level

     From the critical value table this is  [tex]t_{n-1}__{\alpha }} = 1.649[/tex]

So

       [tex]ME = 1.649 * \frac{31.25}{\sqrt{500} }[/tex]

      [tex]ME = 2.2962[/tex]