A researcher surveys middle-school students on their study habits. She finds that in a random sample of 28 middle-school students, the mean amount of time that they spend working on the computer each night is 2.4 hours with a standard deviation of 0.92 hours. She uses the sample statistics to compute a 95% confidence interval for the population mean - the the mean amount of time that all middle-school students spend working on the computer each night. What is the margin of error for this confidence interval

The margin of error is  

Step-by-step explanation:

From the question we are told that

    The sample size is  

     The  sample  mean is  

      The  standard deviation is  

Given that the confidence level is 95% the the level of significance can be evaluated as

Next we obtain the critical value of   from the normal distribution table,the value is  

Generally the margin of error is mathematically represented as

substituting values

answer: 25 is the correct answer

step-by-step explanation:

180°

step-by-step explanation:

sum of equilateral triangle=180°

< n=60°

< m=120°°[angle supplementary of equilateral angle]

< m+< r+< x=360°(sum of exterior angle of triangle)