Please help me, it would be greatly appreciated.

Question

1.) A set of data was collected as shown in the table.
Data value: Frequency:
5. 9
6. 9
7. 14
8. 9
9. 13
10. 7
11. 9
The standard deviation of the data is
A..) 1.90
B.) 2.00
C.) 2.33
D.) 7.93

2.) A group of apples from a particular grower were found to have diameters with a mean of 68.0mm and a standard deviation of 3.9mm. It is expected that 75% of apples will have diameters larger than
A.) 65.4mm
B.) 70.9mm
C.) 71.9mm
D.) 70.6mm

3.) A group of apples from a particular grower were found to have diameters with a mean of 67.0mm and a standard deviation of 4.1mm. It is expected that 30% of apples will have diameters larger than
A.) 71.1mm
B.) 64.9mm
C.) 68.2mm
D.) 69.1mm

Answer 1

#1 See the excellent step-by-step article at

https://mathway.com/examples/Statistics/Frequency-Distribution/Finding-the-Standard-Deviation?id=1040

Use your data values where they used interval-midpoint values (M).

For the others, use the handy tool found at

http://davidmlane.com/hyperstat/z_table.html