Statistics: What is the probability of type I error?

[sanctifier]

Homework Statement

X is a random variable of binomial distribution of parameter n=10 and unknown parameter p. Hypotheses are given as follows:

H_0 \;\; : \;\; p=0.6

H_1 \;\; : \;\; p \neq 0.6

Suppose rejection region for H_0 is \{X \leq 1\} \cup \{X \geq 9\}

Question 1: What is the probability of type I error?

Question 2: If H_1 is changed to "H_1 \;\; : \;\; p =0.3", then what is the probability of type II error?

Homework Equations

Binomial Distribution of parameters n and p: f(x) = \binom{n}x p^x(1-p)^{n-x}

The Attempt at a Solution

Answer 1: Desired probability is

P(X \leq 1,\;\; X \geq 9|p=0.6)=1-P(2\leq X \leq 8|p=0.6)= 1-\sum_{k=2}^8 \binom{10}k 0.6^k(1-0.6)^{10-k} \approx 0.1689

Answer 2:

P(2 \leq X \leq 8|p=0.3) = \sum_{k=2}^8 \binom{10}k 0.3^k(1-0.3)^{10-k} \approx 0.617

Are these answers correct? Thank you in advance!

 

[sanctifier]

Help!

Does anyone know the correct solution?

 

[Ray Vickson]

Help!

Does anyone know the correct solution?

I get 0.04803512320 ≈ 0.0480 for question 1 and .8505479682 ≈ 0.8585 for question 2.