The probability of an impossible event is ........

Can the experimental probability of an event be a negative number? If not,why?

$A$ number is chosen at random from the single-digit natural numbers. The probability that the number chosen is a multiple of $3$ is ...........

The probability of a month of August having $5$ Wednesdays is ............

$100$ seeds were selected at random from each of $5$ bags of seeds,and were kept under standardised conditions equally favourable to germination. After some days,the number of seeds which had germinated in each collection were counted and recorded as follows:

Bag	$1, 2, 3, 4, 5$
Number of seeds germinated	$76, 89, 65, 58, 85$

What is the probability of germination of:
$(1)$ more than $60$ seeds in a bag?
$(2)$ less than $60$ seeds in a bag?
$(3)$ more than $90$ seeds in a bag?

Two dice are thrown simultaneously $500$ times. Each time the sum of two numbers appearing on their tops is noted and recorded as given in the following table:

Sum	Frequency
$2$	$14$
$3$	$30$
$4$	$42$
$5$	$55$
$6$	$72$
$7$	$75$
$8$	$70$
$9$	$53$
$10$	$46$
$11$	$28$
$12$	$15$

If the dice are thrown once more,what is the probability of getting a sum less than or equal to $5$?