Question

the means of two groups of 15 and 20 observations are 20 and 25 respectively.find the mean of all 35 observations.​

Answer 1

Answer:

hey the answer is 20

Step by step explanation:

the solution is in the picture...

Answer 2

The mean of all 35 observations is 22.85

Step-by-step explanation:

$Average = \frac{\text{Sum of all observations}}{\text{No. of observations}}$

The mean of 15 observations is 20

So,$20=\frac{\text{Sum of 15 observations}}{15}\\20 \times 15 = \text{Sum of 15 observations}\\300= \text{Sum of 15 observations}$

The mean of 20 observations is 25

$25=\frac{\text{Sum of 20 observations}}{20}\\25 \times 20 = \text{Sum of 20 observations}\\500 = \text{Sum of 20 observations}$

Sum of 35 observations = 300+500=800

Mean of 35 observations=$\frac{800}{35}=22.85$

Hence The mean of all 35 observations is 22.85

#Learn more:

Find the mean of 2,4,6,8,10,12,14,16​

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