
Answer:
a
  The  correct option is  B
b
  The  correct option is  D
Step-by-step explanation:
From the  question we are told that
   The level of significance is  [tex]\alpha = 0.05[/tex]
   The p-value is  [tex]p = 0.2761[/tex]
Considering question b
   Given that the  [tex]p< \alpha[/tex] then the null hypothesis is  rejected
Considering question b
Given that the original claim is The standard deviation of pulse rates of a certain group of adult males is more than 11 bpm
Then the null hypothesis is  [tex]H_o : \sigma = 11[/tex]
The  reason why the null hypothesis is write like this above is because a null hypothesis expression can not contain only a > or a < but only allows = [tex]\le , \ and \ \ge[/tex]
 and  the alternative hypothesis is  [tex]H_a : \sigma > 11[/tex]
Now given that the null hypothesis is rejected, it mean that there is sufficient evidence to support original claim