Answer:
There is enough statistical evidence to claim that the average length is not 10 cm.
Step-by-step explanation:
The claim that the average lenght is 10 cm, is the null hypothesis (has the "equal" sign). The claim that the average length is not 10 cm is the alternative hypothesis.
The significance level is assumed to be 0.10.
The sample mean is 7 cm and the sample standard deviation is 1 cm.
The degrees of freedom are
The t-statistic is:
The P-value of t=-30 is P=0.
This means there is almost no chance of getting this sample if the mean is really 10 cm.
There is enough statistical evidence to claim that the average length is not 10 cm.