Answer:
0.765
Step-by-step explanation:
The dot plot shows the data
x= 20,21,22,23,24,24,25,25,25,26,26,27,28,29,31
The mean x`= ∑x/n =20+21,+22,+23,+24,+24,+25,+25,+25+,26+,26+,27+,28+,29+,31/15= 376/15
=25.067
where n is the sample size= 15
The standard deviation is σ=2.96
( using calculator)
The standard error is calculated as
SE= σ/√n
SE= 2.96/√15
SE= 0.765
