Answer:
The t value for 99% CI for 21 df is 2.831.
The critical value that should be used in constructing the confidence interval is (64.593, 86.407).
Step-by-step explanation:
Now the sample size is less than 30 and also population standard deviation is not known.
Then we will use t distribution to find CI
t value for 99% CI for 21 df is TINV(0.01,21)=2.831
The margin of error is 
Hence CI is
Answer:
r=4cm
d Diameter
cm
d
r
r
r
d
d
C
A
Unit Conversion:
d=8cm
Using the formula
d=2r
Solving forr
r=d
2=8
2=4cm
Step-by-step explanation:
Answer:
Total surface = 102.4 cm^2 (second answer in the list of options)
Step-by-step explanation:
Notice that we need to add the surface of 4 rectangles, two have smaller sizes than the other two. A pair of rectangles are 7.2 cm x 4 cm = 28.8 cm^2, while the other pair has 7.2 cm x 2 cm = 14.4 cm^2
There are also two equal bases each one of size 4 cm x 2 cm = 8 cm^2
Now we add two of each of the individual surfaces discussed above to complete the total surface area:
2 * 28.8 + 2 * 14.4 + 2 * 8 = 102.4 cm^2
which agrees with the second answer option provided.
Eight ones = 8
Six tens= 60
60 + 8 = 68
