Can someone please explain on how they got the answer with the steps please and thank you in advance

Consider the following table for the total annual returns for a given period of time Series Large-company stocks Small-company stocks Long-term corporate bonds Long-term government bonds Intermediate-term government bonds U.S. Treasury bills Inflation Standard Deviation Average return 11.7 % 16.4 20.6% 33.0 9.3 9.4 5.7 3.1 6.1 5.6 3.1 Requirement 1: What range of returns would you expect to see 95 percent of the time for long-term corporate bonds? (Negative amount should be indicated by a minus sign. Input your answers from lowest to highest to receive credit for your answers. Do not round intermediate calculations. Enter your answers as a percentage rounded to 2 decimal places( e.g., 32.16).) |%to Requirement 2: What about 99 percent of the time? (Negative amount should be indicated by a minus sign. Input your answers from lowest to highest to receive credit for your answers. Do not round intermediate calculations. Enter your answers as a percentage rounded to 2 decimal places (e.g., 32.16).) Expected range of returns | | % to