Answer:
3
Step-by-step explanation:
Ascending order:
4 ,4 , 4 ,4 ,5, 6 ,7 , 7 ,7
9 data: split in
4 ,4 , 4 ,4 | 5 | 6 ,7 , 7 ,7
4 ,4 | 4 ,4 | 5 | 6 ,7 | 7 ,7
(7+7)/2-(4+4)/2
=7-4
=3
we reject H0 and conclude that management's belief about variance is untrue.
H0 : σ² = 250
H1 : σ² ≠ 250
Sample size, n = 25
xbar = 50.6 ; s² = 500
α = 0.01 ;
The test statistic :
χ² = [(n - 1)s²] ÷ σ²
χ² = [(25 - 1)* 500] ÷ 250
χ² = (24 * 500) / 250
χ² = 12000 / 250
χ² = 48
The critical value:
df = n-1 ; 25 - 1 = 24
χ²(0.01/2 ; 24) = 45.559
Decison :
Reject H0 : if |χ² statistic| > critical value
Since 48 > 45.559
Hemce, we reject H0 and conclude that management's belief about variance is untrue.
