Answer:
(1) Yes, because 30 American citizens were sampled.
(2) The probability that the proportion of the 30 Americans sampled that agree climate change is an immediate threat to humanity exceeds 35% is 0.50.
Step-by-step explanation:
We are given that from a representative list of 20677 American citizens, they randomly sampled 30; all responded to their questions.
Previously, 35% of Americans considered climate change an immediate threat to humanity; assume this has not changed.
(1) Yes, it is appropriate to use a normal distribution to describe the sampling distribution of sample proportion because 30 American citizens were sampled.
(2) The z-score probability distribution for the sample proportion is given by;
Z = ~ N(0,1)
where, = sample proportion of Americans who agree climate change is an immediate threat to humanity
p = population proportion of Americans who considered climate change is an immediate threat to humanity
n = sample of American citizens = 30
Now, the probability that the proportion of the 30 Americans sampled that agree climate change is an immediate threat to humanity exceeds 35% is given by = P( > 35%)
P( > 35%) = P( > ) = P(Z > 0) = 0.50
The above probability is calculated by looking at the value of x = 0 in the z table which has an area of 0.50.
Hence, the required probability is 0.50.