Step 1 : Activate Frequency                                 [SM41]

Shift > Mode 

Scroll down

Press '4' > Press '1' to turn ON Frequency

Step 2 : Change to Stats mode                            [M21]

Mode > Press '2' for Stats > Press '1' to choose 1-VAR

Step 3 : Key in data                           

Key in data for 'x' and 'frequency'

Enter number > Press '='

Once data entry completed,

Press 'AC'

Step 4 : Finding Mean and Standard Deviation   [S14]

Shift > Press '1' > Press '4' Var

Press '2' for MEAN > Press '='

Press '3' for STANDARD DEVIATION > Press '='