Stats problems, have work and answer shown

[deaky220]

Homework Statement

the q is , Sheilas measure glucose level one hour after a sugary drink varies according to the normal distribution (u= 125 mg/dl) and r=10 mg/dl. What is the level L such that there is a probability only 0.05 that the mean glucose level of 4 test results falls above L?

Homework Equations

i used x= u(mew) + z * r

The Attempt at a Solution

I did a backwards normal calculation of x= 125 + .5199 (from table A probs) * 10 = 130.199

i think its right but i dunno, does the 4 play a part in my equation or is this the wrong way to do it? ANY information would be helpful

 

[mighty2000]

Hello, thank you for your question. Your approach seems to be correct. To find the level L, you need to use the formula x = u + z * r, where x is the desired level, u is the mean, and r is the standard deviation. The value of z can be found using a normal distribution table or a calculator.

In this case, since the probability of the mean glucose level falling above L is 0.05, the value of z would be 1.645 (found using a normal distribution table). Substituting the values, we get L = 125 + 1.645 * 10 = 140.45 mg/dl.

The number 4 does not play a role in this equation as it represents the number of test results. The question is asking for the level L, which is the same for any number of test results.

Hope this helps! Let me know if you have any other questions.