A statewide real estate sales agency, Farm Associates, specializes in selling farm property in the state of Nebraska. Their records indicate that the mean selling time of farm property in the state of Nebraska. Their records indicate that the mean selling time of farm property is 90 days. Because of recent drought conditions, they believe that the mean selling time is now greater than 90 days. A statewide survey of 100 farms sold recently revealed that the mean selling time was 94 days, with a standard deviation of 22 days. At the .10 significance mean level, has there been an increase in selling time?

My questions:

1. Is the null hypothesis is when the mean is <= 90 and the alternative hypothesis is > 90?

2. What is the critical z-value? I got 1.28, is this right?

3. Is this a two tail test or one tail test? I am guessing it's one tail test

4. I got the z value to be 1.818 is this right?

I need fast answers please