**Soalan 7:**Satu set data mengandungi dua belas nombor positif.

$\text{Diberibahawa}\Sigma {\left(x-\overline{x}\right)}^{2}=600\text{dan}\Sigma {x}^{2}=1032.$

Cari

(a) varians

(b) min

*Penyelesaian*:**(a)**

$\begin{array}{l}\text{Varians}=\frac{\Sigma {\left(x-\overline{x}\right)}^{2}}{N}\\ \text{}=\frac{600}{12}\\ \text{}=50\end{array}$

**(b)**

$\begin{array}{l}\text{Varians}=\frac{\Sigma {x}^{2}}{N}-{\left(\overline{x}\right)}^{2}\\ \text{}50=\frac{1032}{12}-{\left(\overline{x}\right)}^{2}\\ \text{}{\left(\overline{x}\right)}^{2}=86-50\\ \text{}=36\\ \text{}\overline{x}=36\end{array}$

**Soalan 8 (2 markah):**

Jadual menunjukkan maklumat tentang suatu set data.

**Jadual**

Nyatakan

**(a)**nilai

*p*jika

*m*= 20,

**(b)**nilai

*q*jika

*p*= 2.5.

*Penyelesaian*:**(a)**

Sisihan piawai baharu = sisihan piawai asal ×

*p*

20 = 5 ×

*p*

*p*= 4

**(b)**

Median baharu = [median asal ×

*p*] + 1

*q*= 2

*p ×*1

*q*= 2(2.5) + 1

*q*= 5 + 1

*q*= 6

**Soalan 9 (3 markah):**

Jadual menunjukkan taburan skor yang diperolehi sekumpulan murid dalam suatu pertandingan.

**Jadual**

**Nyatakan nilai minimum bagi**

(a)

(a)

*x*jika skor mod ialah 4.

**(b)**Cari min skor bagi taburan itu jika

*x*= 1.

*Penyelesaian*:**(a)**

Nilai minimum bagi

*x*= 8

**(b)**

$\begin{array}{l}\text{Min}\\ =\frac{1\left(3\right)+2\left(6\right)+3\left(7\right)+4\left(1\right)+5\left(1\right)}{3+6+7+1+1}\\ =\frac{45}{18}\\ =2.5\end{array}$