The manager of Sam and Ella's restaurant looked at the receipts for the last two days. The following table shows the range of values:

Amount of Receipt - Frequency of Receipts
0-0.99 --------- ------------- 17
1.00-1.99 --------- ---------- 85
2.00-2.99 - ------ -------------- 140
3.00-3.99 - ----- -------------- 75
4.00-4.99 - ------ --------------- 82
5.00-5.99 - ------ ------------- 73
6.00 - 6.99 - ------- ------------ 62
7.00-7.99 - --- ----------------- 21
8.00-8.99 - ----- -------------- 14
9.00-9.99 - ------------------- 22
10.00-15.00 - ------- ------------- 43

Find:

The standard deviation

MY ANSWER **

4.64?

Tell me if this is right please!