The heights (in cm) of 90 plants in a garden are given below :
`{:("Height (in cm)",58,60,62,64,66,74),("Number of plants",20,25,15,8,12,10):}`
Find the mean height.

The heights (in cm) of 35 students of a class are given below : {:("Height (in cm)",157,152,153,154,155,156),("Number of students",7,4,3,5,9,7):} Find the median height.

The following table shows the heights of 50 students of a class : {:("Height (in cm)",152,148,150,153,149,151,147),("Number of students",8,3,4,7,12,10,6):} Find the mean and the median. Using empirical formula, calculate its mode.

Find the mean height of 65 boys from the following data : {:("Height (in cm)",142,144,146,148,150,152),("Number of boys",10,13,12,7,17,6):}

Heights (in cm) of a sample of 12 fathers and their oldest sons are given below : Find Karl Pearson's correlation coefficient.

find the height of an equlateral triangle having each side 12 cm.

Find the area of a triangle with base 15 cm and height 8 cm.

If the heights of 5 persons are 140 cm, 150cm,158cm, 152 cm and 161 cm respectively. Find the mean height.

The heights of 6 boys are 146 cm, 154 cm, 153 cm, 160 cm, 157 cm and 160 cm. Find their mean height.

The heights of 8 students in a study group are 180 cm, 160 cm, 175 cm, 165 cm , 178 cm, 170 cm, 174 cm and 182 cm. Find their mean height.

If the heights of 5 persons are 140cm, 150cm, 152cm, 158cm and 161cm respectively, find the mean height.