Pembahasan Ujian PAI: A20 – No. 3 – November 2017

PEMBAHASAN

\({S^2} = \frac{1}{{n – 1}}\sum\limits_{i = 1}^n {{{({x_i} – \bar x)}^2}} \)
\(4,8 = \frac{1}{{10 – 1}}\sum\limits_{i = 1}^{10} {{{({x_i} – 0,5)}^2}} \)
\(4,8(9) = \sum\limits_{i = 1}^{10} {({x_i}^2 – {x_i} + 0,25)} \)
\(43,2 = \sum\limits_{i = 1}^{10} {{x_i}^2 – \sum\limits_{i = 1}^{10} {{x_i} + \sum\limits_{i = 1}^{10} {0,25} } } \)
\(43,2 = \sum\limits_{i = 1}^{10} {{x_i}^2 – (n\bar x) + 10(0,25)} \)
\(\sum\limits_{i = 1}^{10} {{x_i}^2 = 43,2 + 5 – 2,5} \)
\(\sum\limits_{i = 1}^{10} {{x_i}^2 = } 45,7\)

Jawaban pada pilihan: B. 45,7