(62,54,49,62,48,53,50) find the mean, MAD, standard deviation , and variance

Anyone know? will mark brainliest if correct!

Need this asap if anyone can i would be very grateful. if you could show workings that would really

On a string instrument, the length of a string varies inversely as the frequency of its vibrations. an 11-inch string has a frequency of 400 cylces per second. find the frequency of a 10-icnch string.