Knitting Problem Lucia is planning to knit a sweater.
At her local craft store, she spies 25 skeins of Abbey Merino yarn in the Lavender Hills color in the bargain bin. She loves it, but she doesn't want to buy it unless she's 95% sure that the sweater will require fewer than 25 skeins. The last 12 sweaters she has knitted have required an average of 23 skeins of yarn with a standard deviation of 1.5.
Note that the "mean" in the hypotheses below can also be called the "expected value," meaning that it's also the best guess for how many skeins it will take to make the next sweater.
Question
What is the alternative hypothesis?

What is the null hypothesis?

Is this a Z question or a T question?

Is this a one-tailed test or a two-tailed test?