Question

Chapter: Measures of Central Tendency


Q8. If 69.5 is the mean of 72, 70, x, 62, 50, 71, 90, 64, 58 and 82: find the value of x.
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Answer 1

Answer:

76

Step-by-step explanation:

Mean =sum of observations /no.of observations

69.5=72+70+x+62+50+71+90+64+58+82

69.5=(619+x)/10

695=619+x

X=76

76

Answer 2

Given

If 69.5 is the mean of 72, 70, x, 62, 50, 71, 90, 64, 58 and 82 find the value of x.

Solution

• Mean = 69.5

Mean = $\sf \dfrac{sum\:of\:observation}{number\:of\:observation}$

=>69.5=72+70+x+62+50+71+90+64+58+82/10

=> 69.5 = 142+x+112+161+204/10

=> 69.5 = 254 + x + 365/10

=> 69.5 = 619 + x/10

=> 695 = 619 + x

=> x = 695 - 619 = 76

Note

★ Median = It is the value of the middle observation

• when n is odd then median = value of the (n+1/2)th observation
• when n is even then median = mean of (n/2)th and (n/2 +1)th observation

★ Mode is the most frequently occurring observation