Astudy claims that college students spend an average of 4 hours or less studying per day. a researcher wants to check if this claim is true. a random sample of 121 college students randomly selected and it showed that average of hours studying per day was 3.15 with a standard deviation of 1.2 hours. using the 10% significance level, can you conclude that the claim college students spend an average of 4 hours or less studying per day is valid?

Let be the population mean.

By observing the given information, we have :-

Since the alternative hypotheses is left tailed so the test is a right-tailed test.

We assume that the time spend by students per day is normally distributed.

Given : Sample size :  n=121 , since n>30 so we use z-test.

Sample mean :

Standard deviation :

Test statistic for population mean :-

Critical value (one-tailed) corresponds to the given significance level :-

Since the observed value of z (-7.79) is less than the critical value (1.2816) , so we do not reject the null hypothesis.

Hence, we conclude that we have enough evidence to accept that the college students spend an average of 4 hours or less studying per day.

hope it you

step-by-step explanation:

sin(7pi/6 - pi/3)  

= sin(7pi/6 - 2pi/6)  

= sin(5pi/6)  

= sin(pi - pi/6)  

= sin(pi/6)  

= 1/2  

sin 7pi/6 - sin pi/3  

= sin (pi + pi/6) - sin pi/3  

= -sin pi/6 - sin pi/3  

= -1/2 - sqrt(3)/2  

= -(1+sqrt(3))2