Testing Hypothesis Probability and Statisitcs Can someone he

Testing Hypothesis

Probability and Statisitcs

Can someone help me on this problem I am a little confused Thanks.
Problem:

Solution

First find out the sample variance = 116388.90

Create null and alternate hypotheses as:

H0: Var = 270400

Ha: Var < 270400

Left tailed test for variances

Test statistic

chi square = (n-1)s^2/sigma^2

= 4.3043

df = 10

p =0.0674

As p < 0.05, we fail to accept null hypothesis.

Variance in birth weight is less than 520^2