Sally is an undergraduate at CSUN and works as a "hair removal technician" at Touch of Class beauty salon. She began taking an intro stat course and it led her to notice that for women who regularly come in for any kind of Bikini wax (e.g. regular, Brazilian, Playboy, Lex Luther) their distribution is normal with an average of 10 waxes a year with a standard deviation of 3. A new Hormone Therapy clinic opened up next door and she wonders if the women receiving treatment there will need more waxing than the typical clientele. She randomly selects 9 of them and on average they come in 14 times over the next year. Do these women receiving hormone therapy need significantly more waxing?

State Null Hypothesis h0 : U ___10

Alternative Hypothesis h1: U_____10

Decide on (usually .05)

Decide on type of test (distribution; z, t, etc.)

Questions to ask:

Can we assume a normally distributed sampling distribution?

In other words, do we have 30+ participants OR a normally distributed population? If yes, then continue.

If no, do not continue, the test cannot be performed.

Do we know the population standard deviation?

If yes, then use to estimate X

and perform a Z-test

_____

________

X

______

If no, then use s to estimate sX and perform a t-test s _____ ________

Find critical value & state decision rule

Critical Value Questions to ask:

Is this a 1-tailed or a 2-tailed test? _________

If it is a t-test what are the degrees of freedom (DF)? _________

If this is a Z-test, find the z-value(s) that correspond to alpha (e.g. 1.96, 1.64) and that is your critical value.

If this is a t-test, use alpha, the number of tails and the degrees of freedom to look up the critical value in a t-table.Find critical value & state decision rule

Critical Value Questions to ask:

a. Is this a 1-tailed or a 2-tailed test? _________ b. If it is a t-test what are the degrees of freedom (DF)? _________

If this is a Z-test, find the z-value(s) that correspond to alpha (e.g. 1.96, 1.64) and that is your critical value. If this is a t-test, use alpha, the number of tails and the degrees of freedom to look up the critical value in a t-table.

Decision Rule In words: If ____observed is larger than ____critical reject the null hypothesis In numbers: If _______ > ________ reject the null hypothesis.