Question

In a certain species of flowering plant, the purple allele P is dominant to the yellow allele p.
A student performed a cross between a purple- flowered plant and a yellow-flowered plant. When planted, the 146 seeds that were produced from the cross matured into 87 plants with purple flowers and 59 plants with yellow flowers.
Calculate the chi-squared value for the null hypothesis that the purple-flowered parent was heterozygous for the flower-color gene. Give your answer to the nearest tenth.

I know this is a Biology question but please help!