Answer:
17 floors
Step-by-step explanation:
1 floor every 4 seconds.
90/4 = 22.5
40 - 22.5 = 17.5
17.5 is 17ish floors, and is the only answer that is close to 17 floors.
Answer:
6
Step-by-step explanation:
Answer: 2.093
Step-by-step explanation:
As per give , we have
Sample size : n= 20
Degree of freedom : df= n-1=19
Significance level : 
Since , the sample size is small (n<30) so we use t-test.
For confidence interval , we find two-tailed test value.
Using students's t-critical value table,
Critical t-value : 
Thus, the critical value for the 95% confidence interval = 2.093