mean and standard deviation + check!

1) The mean and standard deviation of a set of data are two measurements that describe the data. A certain student has written 8 out 10 exams, which are equally weighed. The student misses the 9th exam and receives a score of 0. However, for the last exam, the student studied an incredible amount and scored 100% compare the mean and standard deviation after 8 unit test and after 10 unit test.

My answer:

Both the mean and standard deviation are 50.

2) The following data in the sodium content (in milligrams) of 20 beef hotdogs:

495,477,425,322,482,587,370,322,479,375,330,300,38 6,401, 645, 440,317,319,298, 253

Determine the mean and standard deviation of the data:

My answer:

Mean: 401.15

Standard deviation: 99.84

7) What is the mean and standard deviation?

Value:

4.8

5.2

5.4

5.9

6.5

6.6

Frequency:

25

21

23

17

24

25

My answer:

Mean: 5.74

Standard deviation: 0.69

Can someone please check thanks!!!!!

I know 2 are right but not sure about the first one....

To be honest I can tell you that 2 and 7 are right: but I am not sure about question one maybe someone else can answer well good luck in your studies I am doing statistics and man is it ever confusing but mean and standard deviation are straight foward. well good luck!;)

2) The following data in the sodium content (in milligrams) of 20 beef hotdogs:

495,477,425,322,482,587,370,322,479,375,330,300,38 6,401, 645, 440,317,319,298, 253

Determine the mean and standard deviation of the data:

My answer:

Mean: 401.15

Standard deviation: 99.84

correct good job:)

7) What is the mean and standard deviation?

Value:

4.8

5.2

5.4

5.9

6.5

6.6

Frequency:

25

21

23

17

24

25

My answer:

Mean: 5.74

Standard deviation: 0.69 correct good job:)