Find the mean of the following frequency distribution:

Score $(x)$	$1$	$2$	$3$	$4$	$5$	$6$	$7$
Frequency $(f)$	$5$	$9$	$12$	$17$	$14$	$10$	$6$

$A$ total of $25$ patients admitted to a hospital are tested for blood sugar levels $(mg/dl)$ and the results obtained are as follows:
$\begin{array}{lllll} 87 & 71 & 83 & 67 & 85 \\ 77 & 69 & 76 & 65 & 85 \\ 85 & 54 & 70 & 68 & 80 \\ 73 & 78 & 68 & 85 & 73 \\ 81 & 78 & 81 & 77 & 75 \end{array}$
Find the mean,median,and mode $(mg/dl)$ of the above data.

The width of each of five continuous classes in a frequency distribution is $5$ and the lower class-limit of the lowest class is $10$. The upper class-limit of the highest class is:

The heights (in $cm$) of $12$ students are as follows:
$159, 148, 138, 150, 165, 166, 145, 152, 155, 160, 147, 151$
Find the mean,the median,and the mode.

Draw a histogram for the data given below:

Class	$0-6$	$6-12$	$12-18$	$18-24$	$24-30$	$30-36$
Frequency	$7$	$10$	$12$	$15$	$10$	$6$

If $\bar{x}_{1}, \bar{x}_{2}, \bar{x}_{3}, \ldots, \bar{x}_{n}$ are the means of $n$ groups with $n_{1}, n_{2}, \ldots, n_{n}$ number of observations respectively,then the combined mean $\bar{x}$ of all the groups taken together is given by: