3. The number of t-shirt sales (in pesos) in 10 months are as follows:

165,000 152,000 140,000 167,000 121,000 180,000 110,000 136,000 147,000 174,000

Find the mean.

4. Mean of 9 observations was found to be 35. Later on, it was detected that an observation which was 91, was taken as 19 by mistake. Find the correct mean of the

observations.