Hypothesis testing with one sample

Question

Based on a sample of 400 people 67% owned cats

Answer 1

"Based on a sample of 400 people 67% owned cats " chances of successfully answering this question are zero.

Please do not waste the time of reviewers and tutors trying to answer incomplete or incorrectly posed questions. There IS NO QUESTION TO BE ANSWERED HERE!

If you are going to pose a hypothesis test you require as a minimum.

A null hypothesis must be stated

An alternative hypothesis must be stated or explicitly defined in some way.

Necessary assumptions must be stated (type of distribution, degree of confidence, etc)

"Based on a sample of 400 people 67% owned cats" isn't even a sentence or grammatically correct.

Example: Using a number of people sampled who own cats X = 268 and a sample size of 400 for a binomial distributed variable what are the lower and upper confidence bounds for P(X) (the proportion of people in the population who own cats. ) with a confidence of 99%.

Pos results x sample size n p(x) 99% lcb 99% ucb

method
Jeffreys	268	400	0.6700	0.6077	0.7283

note: this is NOT in any way an answer to a question where the population proportion is given, as in the partial question. It is an example of a fully defined question.