Can you help me on this table please!!!! can u help me answer this for review#16 ?

Question

states in the fall of 1998

state---------- number of public secondary schools

Florida------------------456

Georgia----------------306

Maine-------------------160

Massachusetts------363

North Carolina-------376

New york--------------935

Rhode Island---------54

Virginia-----------------349

1) 1) Find the mean, median,model, and standard deviation of the data. round to the nearest hundredth, if necessary

2) Determine weather the data in the table appears to be positively skewed, or normally distributed. Explain

3) the time a group of high school students arrive home from school each day was found to be normally distributed. the mean time was 3:15 PM and the time has a standard deviation for 15 minutes. What is the probability that a student chosen at random arrives home from school before 2:30 PM?

Answer 1

PROBLEM 1:

Mean:

456 + 306 + 160 + 363 + 376 + 935 + 54 + 349 = 2999

2999/8 = 374.875 = 374.9

Median:

54, 160, 306, 349, 363, 376, 456, 935

349 + 363 = 712

712/2 = 356

Mode:

None

Standard Deviation:

x...........x-374.9........(x-374.9)^2

54.........-320.9..........102,976.81

160.......-214.9..........46,182.01

306.......-68.9............4,747.21

349.......-25.9............670.81

363.......-11.9............141.61

376........1.1..............1.21

456........81.1............6,577.21

935........560.1..........313,712.01

................................475,00...

Add all of the values in the last column together.

Divide that number by (8 - 1) or 7

475008.88/7 = 67585.411

Then take the square root of that number

√67585.411 = 260.496

260.5 = Standard Deviation

PROBLEM 2:

I am not really sure what this question is asking. I have a feeling you will have to calculate a z-score or something but I thought that had to give you a value to test to do that.

x...........x-374.9........(x-374.9)/2...

54.........-320.9..........-1.232

160.......-214.9..........-0.825

306.......-68.9............-0.2645

349.......-25.9............-0.0994

363.......-11.9............-0.0457

376........1.1..............0.00422

456........81.1............0.31132

935........560.1..........2.1501

PROBLEM 3:

I don't know how to solve it because in my math we never learned about normally distribution.