<h2>
Answer with explanation:</h2>
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.
Answer:
50 in total, 45 were eaten
Step-by-step explanation:
If there's only 10% left and 10% is 5 cookies, then that means for every 10% is 5 cookies so 90 x 5 = 45
Answer:
0.3
Step-by-step explanation: