Answer:
a. Mean = 20
Sd = 4
b. Probability of X = 20 = 0.1960
Step-by-step explanation:
we have
n = 25
p = 80% = 0.8
mean = np
= 0.8 * 25
= 20
standard deviation = √np(1-p)
= √25*0.8(1-0.8)
=√4
= 2
probability that exactly 20 favours ban
it follows a binomial distribution
= 25C20 × 0.8²⁰ × 0.2⁵
= 53130 × 0.01153 × 0.00032
= 0.1960
Probability of X = 20 = 0.1960
Answer:4
Step-by-step explanation:
ANSWER
45 green bands
EXPLANATION
The ratio of red hair bands to green hair bands is
5 : 9
The total ratio is:
If there are a total of 70 hair bands,
Then the number of green bands
Simplify
Multiply
Therefore, there are 45 green bands.
Answer:
It has reflectional symmetry with four lines of symmetry.