A consumer group is interested in estimating the proportion of

1. A consumer group is interested in estimating the proportion of packages of ground beef sold at a particular store that have an actual fat content exceeding the fat content stated on the label. About how many packages of ground beef should be tested to estimate the proportion to within plus or minus .05 with 95% confidence, provided that the standard deviation is 1.5 lbs.

2. A survey of 280 homeless persons showed that 63 of them were veterans. Find the upper and lower limit values for the 90% confidence interval

3. A survey of 2070 golfers showed that 347 of them are left handed. Find a point estimate, p the population portion of golfers that are left handed

4. A random sample of 18 families, the average weekly food expense was $95.60 with a sample standard deviation of $22.50. Determine whether a normal distribution (Z values) or a t- distribution should be used or neither of these can be used to construct a confidence interval. Assume normal distribution for food expenses.