The standard deviation of population A is 17.6, and that of population B is 21.2. If sample sizes of 25 and 30 are taken from population A and population B, respectively, what is the standard deviation of the sample mean differences?

About 19.7

Population size:4
Mean (?): 23.45
Standard deviation (?): 4.5986411036305

For a sample this smaller size there are two std deviations. Sample std deviation s(n-1) = 0.550, and population std deviation s(n) = 0.541

If you mean the standard deviation, there are two shifted keys on the third row marked with a lower-case Greek sigma. sigma_xn is the population standard deviation and sigma_xn-1 is the sample standard deviation.

About 29%.

If this is homework, make sure to show your work.

Here are the capabilities of the Casio calculators.
The screen captures may not look like ones taken from the FX-7400G
plus display but the instructions are accurate.
In stat enter the values in List1 and the frequencies in List2 (if doing paired variable statistics)
Press the key corresponding to the CALC tab



Press the 1-var tab and you get the results as seen on the screen with title 1-variable.
Other screens show some two-variable stats or regressions.


Use you knowledge of sample standard deviations and
population standard deviation to select which is relevant to your case.
They are given by xsigma-n and xSigma n-1

Example: Enter the following x variables, and determine the sample and population standard deviations.
x = {1,2,3}

• Press [DATA] and begin to enter the data as indicated into the L1, L2 or L3 lists. To input a data point, type the value and press [ENTER]. Press the down arrow key to move on to the next data point.
• Press [2nd], [STAT], and then choose 1-VAR.
• For the "DATA" option, choose the listname the data is stored in (L1, L2 or L3). For the "FRQ" option, choose "ONE" since this data does not include a frequency list.
• Arrow down to "CALC" and press [ENTER].
  
  Answers should be as follows:
  3:Sx (Sample Standard Deviation) = 1
  4:sx (Population Standard Deviation) = 0.816497
• Press [2nd] [MODE] to exit STAT mode.

Yes. The sample standard deviation is 2nd [sigma x n-1] and the population standard deviation is 2nd [sigma x n].

Hello,
If you want to do statistics with this calculator you press [MODE][3:STAT]. You have then 8 options 1:1-var, 2:A+BX, etc.
For one variable statistics you press 1. Enter the values for the X variable in the template. Once finished you press [SHIFT][1](STAT) then select the value you want ( n, x bar , and the standard deviations (X sigma n) and (X sigma n-1).
Hope it helps.